Retirement Benefits [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension Benefits [Member] Pension Plan [Member] Other Postretirement Benefits [Member] Other Postretirement Benefits Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Weighted average assumptions utilized to determine benefit obligations Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Cash balance interest crediting rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Weighted-Average Interest Crediting Rate Weighted average assumptions utilized to determine net periodic benefit cost (credit) Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Expected long-term rate of return on plan assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Cash balance interest crediting rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Weighted-Average Interest Crediting Rate Health care cost trend rate assumed for next fiscal year Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year Direction and pattern of change for assumed health care cost trend rate Defined Benefit Plan, Assumed Health Care Cost Trend Rate, Description Ultimate health care cost trend rate Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Year that rate reaches ultimate trend rate Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate Leases [Abstract] Accrued Liabilities, Current [Abstract] Interest on debt Interest Payable, Current Employee costs Employee-related Liabilities, Current Estimated rate refund liabilities (Note 19) Customer Refund Liability, Current Contract liabilities (Note 2) Deferred Revenue, Current Asset retirement obligation (Note 12) Asset Retirement Obligation, Current Operating lease liabilities (Note 11) Operating Lease, Liability, Current Other, including other loss contingencies Other Accrued Liabilities, Current Other accrued liabilities Accrued Liabilities, Current Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Trade accounts and other receivables (net of allowance of $6 at December 31, 2019 and $9 at December 31, 2018) Receivables, Net, Current Inventories Inventory, Net Other current assets and deferred charges Other Assets, Current Total current assets Assets, Current Investments Equity Method Investments Property, plant, and equipment – net Property, Plant and Equipment, Net Intangible assets – net of accumulated amortization Intangible Assets, Net (Including Goodwill) Regulatory assets, deferred charges, and other Other Assets, Noncurrent Total assets Assets LIABILITIES AND EQUITY Liabilities [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued liabilities Long-term debt due within one year Long-term Debt and Lease Obligation, Current Total current liabilities Liabilities, Current Long-term debt Long-term Debt and Lease Obligation Deferred income tax liabilities Deferred Tax and Other Liabilities, Noncurrent Regulatory liabilities, deferred income, and other Other Liabilities and Deferred Revenue, Noncurrent Contingent liabilities and commitments (Note 19) Commitments and Contingencies Equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock Preferred Stock, Value, Issued Common stock ($1 par value; 1,470 million shares authorized at December 31, 2019 and December 31, 2018; 1,247 million shares issued at December 31, 2019 and 1,245 million shares issued at December 31, 2018) Common Stock, Value, Issued Capital in excess of par value Additional Paid in Capital, Common Stock Retained deficit Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Treasury stock, at cost (35 million shares of common stock) Treasury Stock, Value Total stockholders’ equity Stockholders' Equity Attributable to Parent Noncontrolling interests in consolidated subsidiaries Stockholders' Equity Attributable to Noncontrolling Interest Total equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and equity Liabilities and Equity Stockholders' Equity Note [Abstract] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Cash Flow Hedges [Member] Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Foreign Currency Translation [Member] Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Pension and Other Post Retirement Benefits [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Total AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Total, Beginning Balance Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Total, Ending Balance Segment Reporting [Abstract] Segment Disclosures [Text Block] Segment Reporting Disclosure [Text Block] Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Transcontinental Gas Pipe Line Company, LLC [Member] Transcontinental Gas Pipe Line Company, LLC [Member] Transcontinental Gas Pipe Line Company, LLC [Member] Northwest Pipeline LLC [Member] Northwest Pipeline LLC [Member] Northwest Pipeline LLC [Member] The Williams Companies, Inc. [Member] Williams Companies Inc [Member] -- None. No documentation exists for this element. -- Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] 7.08% Debentures Due 2026 [Member] 7.08 Percent Debentures Due 2026 [Member] 7.08% Debentures Due 2026 [Member] 7.25% Debentures Due 2026 [Member] 7.25 Percent Debentures Due 2026 [Member] 7.25% Debentures Due 2026 [Member] 7.85% Senior Unsecured Notes Due 2026 [Member] 7.85 Percent Senior Unsecured Notes Due 2026 [Member] 7.85% Senior Unsecured Notes Due 2026 [Member] 4% Senior Unsecured Notes Due 2028 [Member] 4 Percent Senior Unsecured Notes Due 2028 [Member] 4% Senior Unsecured Notes Due 2028 [Member] 5.4% Senior Unsecured Notes Due 2041 [Member] 5.4 Percent Senior Unsecured Notes Due 2041 [Member] 5.4% Senior Unsecured Notes Due 2041 [Member] 4.45% Senior Unsecured Notes Due 2042 [Member] 4.45 Percent Senior Unsecured Notes Due 2042 [Member] 4.45% Senior Unsecured Notes Due 2042 [Member] 4.6% Senior Unsecured Notes Due 2048 [Member] 4.6 Percent Senior Unsecured Notes Due 2048 [Member] 4.6% Senior Unsecured Notes Due 2048 [Member] 7.125% Debentures Due 2025 [Member] 7.125 Percent Debentures Due 2025 [Member] 7.125% Debentures Due 2025 [Member] 4% Senior Unsecured Notes Due 2027 [Member] 4 Percent Senior Unsecured Notes Due 2027 [Member] 4% Senior Unsecured Notes Due 2027 [Member] 4.125% Senior Unsecured Notes Due 2020 [Member] 4.125 Percent Senior Unsecured Notes Due 2020 [Member] 4.125% Senior Unsecured Notes Due 2020 [Member] 5.25% Senior Unsecured Notes Due 2020 [Member] 5.25 Percent Senior Unsecured Notes Due 2020 [Member] 5.25% Senior Unsecured Notes Due 2020 [Member] 4% Senior Unsecured Notes Due 2021 [Member] 4 Percent Senior Unsecured Notes Due 2021 [Member] 4% Senior Unsecured Notes Due 2021 [Member] 7.875% Senior Unsecured Notes Due 2021 [Member] 7.875 Percent Senior Unsecured Notes Due 2021 [Member] 7.875% Senior Unsecured Notes Due 2021 [Member] 3.35% Senior Unsecured Notes Due 2022 [Member] 3.35 Percent Senior Unsecured Notes Due 2022 [Member] 3.35% Senior Unsecured Notes Due 2022 [Member] 3.6% Senior Unsecured Notes Due 2022 [Member] 3.6 Percent Senior Unsecured Notes Due 2022 [Member] 3.6% Senior Unsecured Notes Due 2022 [Member] 3.7% Senior Unsecured Notes Due 2023 [Member] 3.7 Percent Senior Unsecured Notes Due 2023 [Member] 3.7% Senior Unsecured Notes Due 2023 [Member] 4.5% Senior Unsecured Notes Due 2023 [Member] 4.5 Percent Senior Unsecured Notes Due 2023 [Member] 4.5% Senior Unsecured Notes Due 2023 [Member] 4.3% Senior Unsecured Notes Due 2024 [Member] 4.3 Percent Senior Unsecured Notes Due 2024 [Member] 4.3% Senior Unsecured Notes Due 2024 [Member] 4.55% Senior Unsecured Notes Due 2024 [Member] 4.55 Percent Senior Unsecured Notes Due 2024 [Member] 4.55% Senior Unsecured Notes Due 2024 [Member] 3.9% Senior Unsecured Notes Due 2025 [Member] 3.9 Percent Senior Unsecured Notes Due 2025 [Member] 3.9% Senior Unsecured Notes Due 2025 [Member] 4% Senior Unsecured Notes Due 2025 [Member] 4 Percent Senior Unsecured Notes Due 2025 [Member] 4% Senior Unsecured Notes Due 2025 [Member] 3.75% Senior Unsecured Notes Due 2027 [Member] 3.75 Percent Senior Unsecured Notes Due 2027 [Member] 3.75% Senior Unsecured Notes Due 2027 [Member] 7.5% Debentures Due 2031 [Member] 7.5 Percent Debentures Due 2031 [Member] 7.5% Debentures Due 2031 [Member] 7.75% Senior Unsecured Notes Due 2031 [Member] 7.75 Percent Senior Unsecured Notes Due 2031 [Member] 7.75% Senior Unsecured Notes Due 2031 [Member] 8.75% Senior Unsecured Notes Due 2032 [Member] 8.75 Percent Senior Unsecured Notes Due 2032 [Member] 8.75% Senior Unsecured Notes Due 2032 [Member] 6.3% Senior Unsecured Notes Due 2040 [Member] 6.3 Percent Senior Unsecured Notes Due 2040 [Member] 6.3% Senior Unsecured Notes Due 2040 [Member] 5.8% Senior Unsecured Notes Due 2043 [Member] 5.8 Percent Senior Unsecured Notes Due 2043 [Member] 5.8% Senior Unsecured Notes Due 2043 [Member] 5.4% Senior Unsecured Notes Due 2044 [Member] 5.4 Percent Senior Unsecured Notes Due 2044 [Member] 5.4% Senior Unsecured Notes Due 2044 [Member] 5.75% Senior Unsecured Notes Due 2044 [Member] 5.75 Percent Senior Unsecured Notes Due 2044 [Member] 5.75% Senior Unsecured Notes Due 2044 [Member] 4.9% Senior Unsecured Notes Due 2045 [Member] 4.9 Percent Senior Unsecured Notes Due 2045 [Member] 4.9% Senior Unsecured Notes Due 2045 [Member] 5.1% Senior Unsecured Notes Due 2045 [Member] 5.1 Percent Senior Unsecured Notes Due 2045 [Member] 5.1% Senior Unsecured Notes Due 2045 [Member] 4.85 Percent Senior Unsecured Notes Due 2048 [Member] 4.85 Percent Senior Unsecured Notes Due 2048 [Member] 4.85% Senior Unsecured Notes Due 2048 [Member] Various - 7.625% to 10.25% Senior Unsecured Notes and Debentures Due 2019 to 2027 Minimum Interest Rate [Member] Various - 7.625 Percent To 10.25 Percent Senior Unsecured Notes And Debentures Due 2019 To 2027 Minimum Interest Rate [Member] Various - 7.625% to 10.25% Senior Unsecured Notes and Debentures due 2019 to 2027 Minimum Interest Rate [Member] Various - 7.625% to 10.25% Senior Unsecured Notes and Debentures Due 2019 to 2027 Maximum Interest Rate [Member] Various - 7.625 Percent To 10.25 Percent Senior Unsecured Notes And Debentures Due 2019 To 2027 Maximum Interest Rate [Member] Various - 7.625% to 10.25% Senior Unsecured Notes and Debentures due 2019 to 2027 Maximum Interest Rate [Member] Various - 7.625% to 10.25% Senior Unsecured Notes and Debentures Due 2019 to 2027 [Member] Various - 7.625 Percent To 10.25 Percent Senior Unsecured Notes And Debentures Due 2019 To 2027 [Member] Various - 7.625% to 10.25% Senior Unsecured Notes and Debentures due 2019 to 2027 [Member] Dalton [Member] Dalton [Member] Dalton Project [Member] AtlanticSunrise [Member] AtlanticSunrise [Member] Atlantic Sunrise Project [Member] Financing Obligations Approx Int Rate [Member] Financing Obligations Approx Int Rate [Member] Approximate interest rate of both the Atlantic Sunrise and Dalton Other Financing Obligations [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Long-term Debt Long-term Debt and Lease Obligation [Abstract] Long-term debt Long-term Debt, Gross Other financing obligations Other Long-term Debt Long-term debt interest rate Debt Instrument, Interest Rate, Stated Percentage Credit facility loans Long-term Line of Credit Debt issuance costs Unamortized Debt Issuance Expense Net unamortized debt premium (discount) Debt Instrument, Unamortized Discount (Premium), Net Total long-term debt, including current portion Debt and Lease Obligation Long-term debt due within one year Debt Instrument, Term Debt Instrument, Term Allowance for trade accounts and other receivables Accounts Receivable, Allowance for Credit Loss, Current Common stock, shares authorized Common Stock, Shares Authorized Common stock, par value per share Common Stock, Par or Stated Value Per Share Common Stock, shares issued Common Stock, Shares, Issued Treasury stock, shares of common stock Treasury Stock, Shares Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Series B Preferred Stock [Member] Series B Preferred Stock [Member] Class of Stock [Line Items] Class of Stock [Line Items] Common Stock, Dividends, Per Share, Declared Common Stock, Dividends, Per Share, Declared Stock Issued During Period, Shares, New Issues Stock Issued During Period, Shares, New Issues Preferred Stock, Value, Issued Preferred Stock, Dividend Rate, Percentage Preferred Stock, Dividend Rate, Percentage Preferred Stock, Shares Authorized Preferred Stock, Shares Authorized Preferred Stock, Par or Stated Value Per Share Preferred Stock, Par or Stated Value Per Share Shares Issued, Price Per Share Shares Issued, Price Per Share Proceeds from Issuance of Common Stock Proceeds from Issuance of Common Stock Fair Value Disclosures [Abstract] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Fair Value, Recurring [Member] Fair Value, Recurring [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Amount [Member] Reported Value Measurement [Member] Fair Value [Member] Estimate of Fair Value Measurement [Member] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Wiltel Guarantee [Member] Wiltel Guarantee [Member] Guarantee provided in the event of nonpayment by previously owned communications subsidiary, Williams Communications Group (WilTel) Indemnification Agreement [Member] Indemnification Agreement [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Measured on a recurring basis Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract] ARO Trust investments Asset Retirement Obligation, Legally Restricted Assets, Fair Value Energy derivative assets Derivative Asset, Fair Value, Gross Asset Energy derivative liabilities Derivative Liability, Fair Value, Gross Liability Additional disclosures: Additional Fair Value Elements [Abstract] Long-term debt, including current portion Long-term Debt, Fair Value Guarantees Guarantees, Fair Value Disclosure Fair Value, Level 1 to Level 2 Transfers, Amount Fair Value, Assets, Level 1 to Level 2 Transfers, Amount Fair Value, Level 2 to Level 1 Transfers, Amount Fair Value, Assets, Level 2 to Level 1 Transfers, Amount Guarantor Obligations, Maximum Exposure, Undiscounted Guarantor Obligations, Maximum Exposure, Undiscounted Share-based Payment Arrangement, Noncash Expense [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Williams Companies Incentive Plan [Member] Williams Companies Incentive Plan [Member] Williams Companies Incentive Plan [Member] Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [Member] Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Stock options [Member] Share-based Payment Arrangement, Option [Member] Nonvested Restricted Stock Units [Member] Restricted Stock Units (RSUs) [Member] Performance Shares [Member] Performance Shares [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Equity-Based Compensation (Textuals) [Abstract] Stock Based Compensation (Textuals) [Abstract] Stock-Based Compensation. Shares authorized for issuance Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Shares reserved for future issuance Common Stock, Capital Shares Reserved for Future Issuance Shares available for future grants Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant No. of shares purchases by employees Stock Issued During Period, Shares, Employee Stock Purchase Plans Average price of shares purchased Employee Stock Ownership Plan (ESOP), Weighted Average Purchase Price of Shares Purchased Equity-based compensation expense Share-based Payment Arrangement, Expense Tax benefit from equity-based compensation expense Share-based Payment Arrangement, Expense, Tax Benefit Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized [Abstract] Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized [Abstract] Unrecognized equity-based compensation expense Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Unrecognized equity-based compensation expense - Stock Options Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Unrecognized equity-based compensation expense - Restricted Stock Units Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Unrecognized equity-based compensation expense, Weighted-average period of recognition in years Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Rollforward of stock option activity and related information Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Options Outstanding, Beginning Balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Options, Granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Options, Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Options, Cancelled Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period Options Outstanding, Ending Balance Options Exercisable at Period End Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Options, Aggregate Intrinsic Value, Ending Balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Options, Aggregate Intrinsic Value, Exercisable at Period End Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Total intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Tax benefits realized on options exercised Share-based Payment Arrangement, Exercise of Option, Tax Benefit Cash received from the exercise of options Proceeds from Stock Options Exercised Stock Options Outstanding, Weighted Average Remaining Contractual Life Share-based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term Stock Options Exercisable, Weighted Average Remaining Contractual Life Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Remaining Contractual Term Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Options, Weighted Average Exercise Price, Beginning Balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Options, Weighted Average Exercise Price, Granted Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Options, Weighted Average Exercise Price, Exercised Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Options, Weighted Average Exercise Price, Cancelled Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Options, Weighted Average Exercise Price, Ending Balance Options, Weighted Average Exercise Price, Exercisable at Period End Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Estimated fair value at date of grant of options for common stock granted Estimated fair value at date of grant of options for common stock granted [Abstract] Estimated fair value at date of grant of options for common stock granted. Weighted-average grant date fair value of options for our common stock granted during the year, per share Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted-average assumptions: Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Weighted Average Volatility Rate Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected life (years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Duration Of Base Term For Peer Group Historical Volatility Measurement Duration Of Base Term For Peer Group Historical Volatility Measurement Duration Of Base Term For Peer Group Historical Volatility Measurement Rollforward of nonvested restricted stock unit activity and related information Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Restricted Stock Units, Nonvested shares, Beginning Balance Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Restricted Stock Units, Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Restricted Stock Units, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Restricted Stock Units, Vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Restricted Stock Units, Nonvested shares, Ending Balance Performance based nonvested restricted stock units as a percent of total nonvested restricted stock units outstanding Performance Based Nonvested Restricted Stock Units As Percent Of Total Nonvested Restricted Stock Units Outstanding Performance based nonvested restricted stock units as a percent of total nonvested restricted stock units outstanding. Range of vested shares based on extent to which certain financial targets are achieved Range Of Vested Shares Based On Extent To Which Certain Financial Targets Range Of Vested Shares Based On Extent To Which Certain Financial Targets Are Achieved Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Restricted Stock Units, Nonvested, Weighted-Average Fair Value, Beginning Balance Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Weighted-average grant date fair value of restricted stock units granted during the year, per share Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Restricted Stock Units, Forfeited, Weighted-Average Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Restricted Stock Units, Vested, Weighted-Average Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Restricted Stock Units, Nonvested, Weighted-Average Fair Value, Ending Balance Restricted Stock Units, Vested in Period, Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Reconciliation of revenue from segment to consolidated [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Reconciliation of Modified EBITDA to Net income (loss) [Table Text Block] Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Total assets and equity method investments by reporting segment [Table Text Block] Reconciliation of Assets from Segment to Consolidated [Table Text Block] Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Statement, Equity Components [Axis] Preferred Stock Preferred Stock [Member] Common Stock Common Stock [Member] Capital in Excess of Par Value Additional Paid-in Capital [Member] Retained Deficit Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) Treasury Stock Treasury Stock [Member] Total Stockholders' Equity Parent [Member] Noncontrolling Interests Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Beginning balance Adoption of new accounting standard New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification Net income (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest WPZ Merger (Note 1) Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Issuance of stock (Note 16) Stock Issued During Period, Value, New Issues Cash dividends – common stock Dividends, Common Stock, Cash Dividends and distributions to noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Stock-based compensation and related common stock issuances, net of tax Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture Sales of limited partner units of Williams Partners L.P. Noncontrolling Interest, Increase from Sale of Parent Equity Interest Changes in ownership of consolidated subsidiaries, net Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net Contributions from noncontrolling interests Contributions From Noncontrolling Interests Noncontrolling interest, increase from contributions from noncontrolling interest holders. Deconsolidation of subsidiary (Note 6) Noncontrolling Interest, Decrease from Deconsolidation Other Stockholders' Equity, Other Net increase (decrease) in equity Stockholders' Equity, Period Increase (Decrease) Ending balance Lease, Cost [Table Text Block] Lease, Cost [Table Text Block] Lessee, Operating Lease, Liability, Maturity [Table Text Block] Lessee, Operating Lease, Liability, Maturity [Table Text Block] Equity-Based Compensation [Text Block] Share-based Payment Arrangement [Text Block] Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Business Acquisition [Line Items] Business Acquisition [Line Items] Schedule of Business Acquisitions, by Acquisition [Table Text Block] Schedule of Business Acquisitions, by Acquisition [Table Text Block] Business Acquisition, Pro Forma Information [Table Text Block] Business Acquisition, Pro Forma Information [Table Text Block] Property, Plant and Equipment [Abstract] Asset Retirement Obligations Asset Retirement Obligation [Abstract] Asset Retirement Obligations, Noncurrent Asset Retirement Obligations, Noncurrent Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Beginning balance Asset Retirement Obligation Liabilities incurred Asset Retirement Obligation, Liabilities Incurred Liabilities settled Asset Retirement Obligation, Liabilities Settled Accretion expense Asset Retirement Obligation, Accretion Expense Revisions (1) Asset Retirement Obligation, Revision of Estimate Ending balance Unusual or Infrequent Item [Table] Unusual or Infrequent Item, or Both [Table] Unusual or Infrequent Item [Axis] Unusual or Infrequent Item, or Both [Axis] Unusual or Infrequent Item [Domain] Unusual or Infrequent Item, or Both [Domain] Asset Retirement Obligation Costs [Member] Asset Retirement Obligation Costs [Member] Unusual or Infrequent Item [Line Items] Unusual or Infrequent Item, or Both [Line Items] Transco's annual funding commitment for ARO Other Commitment, Due in Next Twelve Months Income Tax Disclosure [Abstract] Effective Income Tax Rate Reconciliation [Abstract] Effective Income Tax Rate Reconciliation, Amount [Abstract] Provision (benefit) at statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Increases (decreases) in taxes resulting from: Increases Decreases In Taxes Resulting From [Abstract] Increases (decreases) in taxes resulting from. Impact of nontaxable noncontrolling interests Effective Income Tax Rate Reconciliation, Noncontrolling Interest Income (Loss), Amount Federal Tax Reform rate change Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount State income taxes (net of federal benefit) Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount State deferred income tax rate change Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Foreign operations – net (including tax effect of Canadian Sale) Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount Federal valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Other – net Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount Provision (benefit) for income taxes Income Tax Expense (Benefit) Income Tax Contingency [Table] Income Tax Contingency [Table] Stock Conversion Description [Axis] Stock Conversion Description [Axis] Conversion of Stock, Name [Domain] Conversion of Stock, Name [Domain] WPZ Merger Public Unit Exchange [Member] WPZ Merger Public Unit Exchange [Member] WPZ Merger Public Unit Exchange [Member] Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] Expiration None [Member] Expiration None [Member] Expiration None [Member] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Internal Revenue Service (IRS) [Member] Internal Revenue Service (IRS) [Member] Income Tax Authority, Name [Axis] Income Tax Authority, Name [Axis] Income Tax Authority, Name [Domain] Income Tax Authority, Name [Domain] Income Tax Contingency [Line Items] Income Tax Contingency [Line Items] Deferred income tax liabilities: Deferred Tax Liabilities, Gross [Abstract] Property, plant and equipment Deferred Tax Liabilities, Property, Plant and Equipment Investments Deferred Tax Liabilities, Investment in Noncontrolled Affiliates Other Deferred Tax Liabilities, Other Total deferred income tax liabilities Deferred Tax Liabilities, Gross Deferred income tax assets: Deferred Tax Assets, Net [Abstract] Accrued liabilities Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Minimum tax credit Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax Foreign tax credit Deferred Tax Assets, Tax Credit Carryforwards, Foreign Federal loss carryovers Deferred Tax Assets, Operating Loss Carryforwards, Domestic State losses and credits Deferred Tax Assets, Operating Loss Carryforwards, State and Local Other Deferred Tax Assets, Other Total deferred income tax assets Deferred Tax Assets, Gross Less valuation allowance Deferred Tax Assets, Valuation Allowance Net deferred income tax assets Deferred Tax Assets, Net of Valuation Allowance Overall net deferred income tax liabilities Deferred Tax Liabilities, Net Commitments and Contingencies Disclosure [Abstract] Contingent Liabilities and Commitments [Text Block] Commitments and Contingencies Disclosure [Text Block] SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] Deferred Tax Asset Valuation Allowance [Member] SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] Valuation And Qualifying Accounts SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] Beginning Balance SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount Additions Charged (Credited) To Cost and Expenses SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Cost and Expense Additions Other SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Other Account Deductions SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction Ending Balance Organization, Consolidation and Presentation of Financial Statements [Abstract] General, Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies [Text Block] Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] Income Statement [Abstract] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Other Nonoperating Income (Expense) [Member] Other Nonoperating Income (Expense) [Member] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Service [Member] Service [Member] NonRegulated Service Commodity Consideration [Member] NonRegulated Service Commodity Consideration [Member] NonRegulated Service Commodity Consideration [Member] Product [Member] Product [Member] Oil and Gas, Purchased [Member] Oil and Gas, Purchased [Member] Natural Gas Purchased For Shrink [Member] Natural Gas Purchased For Shrink [Member] Natural Gas Purchased For Shrink Revenues: Revenues [Abstract] Revenues Revenues Costs and expenses: Costs and Expenses [Abstract] Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization Operating and maintenance expenses Operating Costs and Expenses Depreciation and amortization expenses Depreciation, Depletion and Amortization Selling, general, and administrative expenses Selling, General and Administrative Expense Impairment of certain assets (Note 18) Other Asset Impairment Charges Gain on sale of certain assets and businesses (Note 3) Gain (Loss) on Disposition of Assets Regulatory Charges resulting From Tax Reform (Note 1) Regulatory Charges In Operating Expense Resulting From Tax Reform Regulatory charges in Operating Expense resulting from the enactment of the Tax Cuts and Jobs Act in 2017. Other (income) expense – net Other Operating Income (Expense), Net Total costs and expenses Costs and Expenses Operating income (loss) Operating Income (Loss) Equity earnings (losses) Income (Loss) from Equity Method Investments Other investing income (loss) – net Investment Income, Nonoperating Interest incurred Interest Costs Incurred Interest capitalized Interest Costs Capitalized Adjustment Other income (expense) – net Other Nonoperating Income (Expense) Income (loss) from continuing operations before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Provision (benefit) for income taxes Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Net income (loss) Less: Net income (loss) attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Amounts attributable to The Williams Companies, Inc. available to common stockholders: Income Amounts Attributable to Parent, Disclosures [Abstract] Net income (loss) attributable to The Williams Companies, Inc. Net Income (Loss) Attributable to Parent Preferred stock dividends (Note 16) Preferred Stock Dividends, Income Statement Impact Net income (loss) available to common stockholders Net Income (Loss) Available to Common Stockholders, Basic Income (loss) from continuing operations available to common stockholders Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Basic earnings (loss) per common share: Earnings Per Share, Basic [Abstract] Net income (loss) Earnings Per Share, Basic Basic Income (Loss) from Continuing Operations, Per Basic Share Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Weighted-average shares (thousands) Weighted Average Number of Shares Outstanding, Basic Diluted earnings (loss) per common share: Earnings Per Share, Diluted [Abstract] Net income (loss) Earnings Per Share, Diluted Diluted Income (Loss) from Continuing Operations, Per Diluted Share Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Weighted-average shares (thousands) Weighted Average Number of Shares Outstanding, Diluted Stockholders' Equity [Text Block] Stockholders' Equity Note Disclosure [Text Block] Related Party Transactions [Abstract] Related Party Transactions [Text Block] Related Party Transactions Disclosure [Text Block] Nonqualified Plan [Member] Nonqualified Plan [Member] Qualified Plan [Member] Qualified Plan [Member] Benefit Plan Disclosure [Line Items] Expected total plans contribution, approximate Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Expected benefit payments Defined Benefit Plan, Expected Future Benefit Payment [Abstract] 2020 Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year Two 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Three 2023 Defined Benefit Plan, Expected Future Benefit Payment, Year Four 2024 Defined Benefit Plan, Expected Future Benefit Payment, Year Five 2025-2029 Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter Employer's contributions charged to expense under defined contribution plans Defined Contribution Plan, Cost Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Intersegment Eliminations [Member] Intersegment Eliminations [Member] Operating Segments [Member] Operating Segments [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Atlantic Gulf [Member] Atlantic Gulf [Member] -- None. No documentation exists for this element. -- Northeast G And P [Member] Northeast G And P [Member] -- None. No documentation exists for this element. -- West [Member] West [Member] -- None. No documentation exists for this element. -- Other [Member] Corporate and Other [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Reconciliation of Modified EBITDA to Net Income (Loss) Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract] Modified EBITDA Modified EBITDA Earnings Loss Amount of our segment operating performance measure, calculated as Net income (loss) before Provision (benefit) for income taxes; Interest incurred, net of interest capitalized; Equity earnings (losses); Impairment of equity-method investments; Other investing income (loss) – net; Impairment of goodwill; Depreciation and amortization expense; Accretion expense associated with asset retirement obligations for nonregulated operations. This measure is further adjusted to include our proportionate share (based on ownership interest) of Modified EBITDA from our equity-method investments calculated consistently with the definition described above. Accretion expense associated with asset retirement obligations for nonregulated operations Asset Retirement Obligation Accretion Expense For Nonregulated Operations Asset Retirement Obligation Accretion Expense For Nonregulated Operations Depreciation and amortization expenses Proportional Modified EBITDA Equity Method Investments Proportional Modified EBITDA Equity Method Investments Proportional Modified EBITDA Equity Method Investments Interest Expense Interest Expense (Provision) benefit for income taxes Revenue Recognition [Abstract] Revenue Recognition [Text Block] Revenue from Contract with Customer [Text Block] Change in plan assets: Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Fair value of plan assets at beginning of year Defined Benefit Plan, Plan Assets, Amount Actual return on plan assets Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Employer contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Plan participants’ contributions Defined Benefit Plan, Plan Assets, Contributions by Plan Participant Benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Settlements Defined Benefit Plan, Plan Assets, Payment for Settlement Net increase (decrease) in fair value of plan assets Defined Benefit Plan, Plan Assets, Period Increase (Decrease) Fair value of plan assets at end of year Funded status — overfunded (underfunded) Defined Benefit Plan, Funded (Unfunded) Status of Plan Accumulated benefit obligation Defined Benefit Plan, Accumulated Benefit Obligation Overfunded/(underfunded) status of our pension plans and other postretirement benefit plans Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract] Noncurrent assets Assets for Plan Benefits, Defined Benefit Plan Current liabilities Liability, Defined Benefit Plan, Current Noncurrent liabilities Liability, Defined Benefit Plan, Noncurrent Pension Plans with Project Benefit Obligation in Excess of Plan Assets [Abstract] Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract] Projected benefit obligation Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation Plan assets Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets Pension Plans with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract] Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract] Accumulated benefit obligation Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation Plan assets Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets Pre-tax amounts not yet recognized in net periodic benefit cost (credit) Pre Tax Amounts Not Yet Recognized In Net Periodic Benefit Expense [Abstract] Pre-tax amounts not yet recognized in net periodic benefit expense. Amounts included in Accumulated other comprehensive income (loss): Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract] Net actuarial loss Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline: Net Regulatory Assets [Abstract] Net actuarial gain Amounts Included In Net Regulatory Liabilities Assets Associated With Our Federal Energy Regulatory Commission Regulated Gas Pipelines Net Actuarial Gain Loss Amounts Included In Net Regulatory Liabilities (Assets) Associated With Our Federal Energy Regulatory Commission Regulated Gas Pipelines Net Actuarial Gain (Loss) Net regulatory liabilities Net Regulatory Assets Variable Interest Entity Disclosures [Abstract] -- None. No documentation exists for this element. -- Schedule of Variable Interest Entities [Table Text Block] Schedule of Variable Interest Entities [Table Text Block] Components of net periodic benefit cost (credit): Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Amortization of prior service credit Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Amortization of net actuarial loss Defined Benefit Plan, Amortization of Gain (Loss) Net actuarial loss from settlements Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Reclassification to regulatory liability Reclassification Of Employee Benefit Cost / Credit To Regulatory Asset / Liability Reclassification of employee benefit cost / credit not collected in rates to regulatory asset / liability Net periodic benefit cost (credit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss): Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract] Net actuarial gain (loss) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax Amortization of prior service credit Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Amortization of net actuarial loss Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Net actuarial loss from settlements Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss) Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax Other changes in plan assets and benefit obligations recognized in regulatory (assets) and liabilities: OtherChangesInPlanAssetsAndBenefitObligationsRecognizedInRegulatoryAssetsLiabilities [Abstract] Other changes in plan assets and benefit obligations for other postretirement benefit plans recognized in regulatory assets/liabilities associated with Transco and Northwest Pipeline Net actuarial gain (loss) Defined Benefit Plan Actuarial Net Gains Losses In Regulatory Liabilities Assets Defined Benefit Plan, Actuarial Net Gains (Losses) In Regulatory Liabilities (Assets) Amortization of prior service credit Defined Benefit Plan Amortization From Regulatory Assets Liabilities Of Prior Service Cost Credit Defined Benefit Plan Amortization From Regulatory Assets (Liabilities) Of Prior Service Cost (Credit) Investments [Abstract] Realized Gain (Loss) on Investments [Table Text Block] Realized Gain (Loss) on Investments [Table Text Block] Investments [Table Text Block] Equity Method Investments [Table Text Block] Contributions [Table Text Block] EquityMethodInvestmentContributionsTextBlock [Table Text Block] Tabular disclosure of contributions paid to companies accounted for by the equity method. Dividends and distributions [Table Text Block] Equity Method Investment Dividends Or Distributions [Text Block] Tabular disclosure of dividends or distributions received from companies accounted for by the equity method. Summarized Financial Position and Results of Operations of Equity Method Investments [Table Text Block] Equity Method Investment Summarized Financial Position And Results Of Operations [Table Text Block] Tabular disclosure of summarized financial position and results of operations of equity method investments. Reconciliation of Revenue from Segments to Consolidated [Table] Reconciliation of Revenue from Segments to Consolidated [Table] Segment revenues [Line Items] Segment Reporting, Revenue Reconciling Item [Line Items] Other financial information: Other Financial Information [Abstract] Other financial information. Additions to long-lived assets Payments to Acquire Productive Assets Proportional Modified EBITDA Equity Method Investments Employee Benefit Plans [Text Block] Pension and Other Postretirement Benefits Disclosure [Text Block] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] NonRegulated Service Monetary Consideration [Member] NonRegulated Service Monetary Consideration [Member] NonRegulated Service Monetary Consideration [Member] Regulated Service [Member] Regulated Service [Member] Regulated Service [Member] Other Service [Member] Other Service [Member] Other Service [Member] NGL And Natural Gas Product Sales [Member] NGL And Natural Gas Product Sales [Member] NGL and Natural Gas Product Sales [Member] Other Product Sales [Member] Other Product Sales [Member] Other Product Sales [Member] Subsegments [Axis] Subsegments [Axis] Subsegments [Domain] Subsegments [Domain] Transco [Member] Transco [Member] Transco Geographical [Member] Northwest Pipeline [Member] Northwest Pipeline [Member] Northwest Pipeline Geographical [Member] Atlantic Gulf Midstream [Member] Atlantic Gulf Midstream [Member] Atlantic Gulf Midstream [Member] West Midstream [Member] West Midstream [Member] West Midstream [Member] Corporate and Other [Member] Intercompany Eliminations [Member] Intercompany Eliminations [Member] Intercompany Eliminations Geographical [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue from Contract with Customer, Excluding Assessed Tax Revenue from Contract with Customer, Excluding Assessed Tax Revenue Not from Contract with Customer Revenue Not from Contract with Customer Total revenues Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 1, 2 and 3 [Member] Fair Value, Inputs, Level 1, 2 and 3 [Member] Fair Value Measured at Net Asset Value Per Share [Member] Fair Value Measured at Net Asset Value Per Share [Member] Defined Benefit Plan by Plan Asset Categories [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] Cash management fund Money Market Funds [Member] Equity Securities Equity Securities [Member] Fixed Income Securities Fixed Income Securities [Member] Fixed income securities - U.S. Treasury securities US Treasury Securities [Member] Fixed income securities - Government and municipal bonds US States and Political Subdivisions Debt Securities [Member] Fixed income securities - Mortgage and asset-backed securities Asset-backed Securities [Member] Fixed income securities - Corporate bonds Corporate Debt Securities [Member] Other Other than Securities Investment [Member] Insurance company investment contracts and other Insurance company investment contracts and other [Member] Insurance company investment contracts and other. Mutual fund - Municipal bonds Mutual Fund [Member] Commingled investment funds - equities - U.S. large cap EquityFundsUSLargeCap [Member] EquityFundsUSLargeCap [Member] Commingled investment funds - Global large and mid cap Equity Funds Global [Member] Commingled investment funds - equities - Global [Member] Commingled investment funds - equities - International small cap EquityFundsNonUSSmallCap [Member] EquityFundsNonUSSmallCap [Member] Commingled investment funds - equities - International emerging markets EquityFundsNonUSEmergingMarkets [Member] EquityFundsNonUSEmergingMarkets [Member] Commingled investment funds - equities - International developed markets EquityFundsNonUSDevelopedMarkets [Member] EquityFundsNonUSDevelopedMarkets [Member] Commingled investment funds - fixed income - U.S. long and intermediate duration FixedIncomeFundsUSLongDuration [Member] FixedIncomeFundsUSLongDuration [Member] Commingled investment funds - fixed income - Corporate bonds FixedIncomeFundsCorporateBonds [Member] FixedIncomeFundsCorporateBonds [Member] Proportion of assets subjected to income tax Proportion Of Other Postretirement Benefit Plan Assets Subjected To Income Tax Proportion of other postretirement benefit plan assets subjected to income tax. Plan asset target allocation Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Maximum percentage of total stock portfolio invested in the common stock of any one corporation Maximum Percentage Of Total Stock Portfolio Invested In Common Stock Of Any One Corporation Maximum percentage of total stock portfolio invested in the common stock of any one corporation. Maximum percentage of portfolio invested in fixed income securities of any one issuer with exception of bond index funds and U. S. government guaranteed and agency securities Maximum Percentage Of Portfolio Invested In Debt Securities Of Any One Issuer With Exception Of US Government Guaranteed And Agency Securities Maximum Percentage of Portfolio Invested in Debt Securities of Any One Issuer with Exception of US Government Guaranteed and Agency Securities Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period Weighted average duration of fixed income security portfolio Weighted Average Duration Of Fixed Income Security Portfolio 1 Weighted average duration of fixed income security portfolio Fair value, plan assets, Level 1 to Level 2 transfers, amount DefinedBenefitPlanFairValueAssetsLevel1ToLevel2TransfersAmount DefinedBenefitPlanFairValueAssetsLevel1ToLevel2TransfersAmount Fair value, plan assets, Level 2 to Level 1 transfers, amount DefinedBenefitPlanFairValueAssetsLevel2ToLevel1TransfersAmount DefinedBenefitPlanFairValueAssetsLevel2ToLevel1TransfersAmount Fair values of plan assets Fair Values Of Plan Assets [Abstract] Fair values of plan assets [Abstract] Total assets at fair value Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Jackalope Gas Gathering Services LLC [Member] Jackalope Gas Gathering Services LLC [Member] Jackalope Gas Gathering Services LLC [Member] Utica East Ohio Midstream, LLC Acquisition [Member] Utica East Ohio Midstream, LLC Acquisition [Member] Utica East Ohio Midstream, LLC Acquisition [Member] Goodwill [Line Items] Goodwill [Line Items] Goodwill Goodwill Goodwill, Period Increase (Decrease) Goodwill, Period Increase (Decrease) Other Income and Expenses [Abstract] 4.875% Senior Unsecured Notes Due 2024 [Member] 4.875 Percent Senior Unsecured Notes Due 2024 [Member] 4.875% Senior Unsecured Notes Due 2024 [Member] Pension Plan [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Disposal Group, Not Discontinued Operations [Member] Disposal Group, Not Discontinued Operations [Member] Other Operating Income (Expense) [Member] Other Operating Income (Expense) [Member] Selling, general and administrative expenses [Member] Selling, General and Administrative Expenses [Member] Selling, general, and administrative expenses and Operating and maintenance expenses [Member] Selling, General, And Administrative Expenses And Operating And Maintenance Expenses [Member] Selling, general, and administrative expenses and Operating and maintenance expenses [Member] Other income (expense) - net [Member] Deferred Taxes On Equity Funds Used During Construction [Member] Deferred Taxes On Equity Funds Used During Construction [Member] Deferred taxes on equity funds used during construction [Member] Other [Member] Other [Member] Other [Member] Business Interruption Loss [Axis] Business Interruption Loss [Axis] Business Interruption Loss [Domain] Business Interruption Loss [Domain] Amortization of regulatory assets associated with asset retirement obligations Amortization of Regulatory Asset Accrual of regulatory liability related to overcollection of certain employee expenses Accrual Of Regulatory Liability The expense charged against earnings during the period related to overcollection of certain employee expenses related to rate cases. Project development costs related to Constitution Costs Incurred, Development Costs Regulatory Charge Resulting From Tax Rate Change Regulatory Charge Resulting From Tax Rate Change Regulatory charge resulting from tax rate change Gains on asset retirements Regulatory Charges In Operating Expense Resulting From Tax Reform Tangible Asset Impairment Charges Tangible Asset Impairment Charges Gains on contract settlements and terminations Gain (Loss) on Contract Termination Regulatory Benefit Resulting From Tax Rate Change Regulatory Benefit Resulting From Tax Rate Change wmb_RegulatoryBenefitResultingFromTaxRateChange Gain on sale of Refinery Grade Propylene Splitter Noncash Contribution Expense Noncash Contribution Expense WPZ Merger WPZ Merger WPZ Merger-rollup of WPZ into WMB Allowance for funds used during construction, capitalized cost of equity Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Debt Instrument, Unamortized Discount (Premium), Net Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Regulatory charges resulting from Tax Reform (Note 1) RegulatoryChargesResultingFromTaxReform Regulatory charges resulting from the enactment of the Tax Cuts and Jobs Act in 2017. Severance and other related costs Severance Costs Statement of Comprehensive Income [Abstract] Comprehensive income (loss): Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Cash flow hedging activities: Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract] Net unrealized gain (loss) from derivative instruments, net of taxes of $1 and $2 in 2018 and 2017, respectively Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Reclassifications into earnings of net derivative instruments (gain) loss, net of taxes of ($1) and ($1) in 2018 and 2017, respectively Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Foreign currency translation activities: Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract] Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Pension and other postretirement benefits: Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax [Abstract] Amortization of prior service cost (credit) included in net periodic benefit cost (credit), net of taxes of $2 in 2017 Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax Net actuarial gain (loss) arising during the year, net of taxes of ($20), $3, and ($15) in 2019, 2018, and 2017, respectively Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax Amortization of actuarial (gain) loss and net actuarial loss from settlements included in net periodic benefit cost (credit), net of taxes of ($4), ($11), and ($37) in 2019, 2018, and 2017, respectively Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax Other comprehensive income (loss) Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Less: Comprehensive income (loss) attributable to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive Income (loss) attributable to The Williams Companies, Inc. Comprehensive Income (Loss), Net of Tax, Attributable to Parent Reconciliation of Assets from Segment to Consolidated [Table] Reconciliation of Assets from Segment to Consolidated [Table] Segment Reporting, Asset Reconciling Item [Line Items] Segment Reporting, Asset Reconciling Item [Line Items] Total assets Equity-method investments Income Tax Expense (Benefit), Continuing Operations [Abstract] Schedule of Components of Provision (benefit) for income taxes [Table Text Block] Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Provision for income taxes at federal statutory rate [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Deferred tax liabilities and Deferred tax assets [Table Text Block] Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Reconciliation of unrecognized tax benefits [Table Text Block] Summary of Income Tax Contingencies [Table Text Block] Regulatory Assets and Liabilities [Table Text Block] Schedule of Regulatory Assets and Liabilities [Text Block] Investing Activities [Text Block] Equity Method Investments and Joint Ventures Disclosure [Text Block] Property, Plant, and Equipment [Table Text Block] Property, Plant and Equipment [Table Text Block] Asset Retirement Obligation [Table Text Block] Asset Retirement Obligation Disclosure [Text Block] Stock Option Rollfoward and related information [Table Text Block] Share-based Payment Arrangement, Option, Activity [Table Text Block] Cash Proceeds Received and Tax Benefit from Share-based Payment Awards [Table Text Block] Cash Proceeds Received and Tax Benefit from Share-based Payment Awards [Table Text Block] Stock Options Schedule of Valuation Assumptions [Table Text Block] Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Nonvested Restricted Stock Unit Rollforward and related information [Table Text Block] Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Other restricted stock unit information [Table Text Block] Other restricted stock unit information [Text Block] Other restricted stock unit information. Earnings Per Share [Abstract] Earnings (loss) per common share [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Line of Credit Facility [Table] Line of Credit Facility [Table] Quarters Ending Time [Axis] Quarters Ending Time [Axis] Quarters Ending Time [Axis] Quarters Ending Time [Domain] Quarters Ending Time [Domain] [Domain] for Quarters Ending Time [Axis] Sep18Dec18Mar19Jun19 [Member] Sep18Dec18Mar19Jun19 [Member] Each fiscal quarter end from Sep18 through Jun19 Sep19Dec19 [Member] Sep19Dec19 [Member] Fiscal quarter end at Sep19 and Dec19 Mar20 And Subsequent Quarters [Member] Mar20 And Subsequent Quarters [Member] For fiscal quarter end Mar20 and each subsequent quarter Williams Companies Inc [Member] Williams Partners L.P. [Member] Williams Partners LP [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] SwingLineLoan [Member] SwingLineLoan [Member] Swing line loan [Member] Commercial paper [Member] Commercial Paper [Member] Letters of credit [Member] Letter of Credit [Member] Letters Of Credit Under Certain Bilateral Bank Agreements [Member] Letters Of Credit Under Certain Bilateral Bank Agreements [Member] Letters of Credit Under Certain Bilateral Bank Agreements [Member] Credit Facility and Commercial Paper [Line Items] Line of Credit Facility [Line Items] Credit facility, capacity Line of Credit Facility, Maximum Borrowing Capacity Debt Instrument, Face Amount Debt Instrument, Face Amount Credit facility, loans outstanding Credit facility, letters of credit outstanding Letters of Credit Outstanding, Amount Commercial paper, outstanding Commercial Paper Commercial paper, maximum maturity Additional amount by which credit facility can be increased Additional Amount By Which Credit Facility Can Be Increased Additional amount by which the credit facility can be increased. Maximum ratio of debt to EBITDA Maximum Ratio Of Debt To EBITDA Maximum Ratio Of Debt To EBITDA Maximum ratio of debt to EBITDA after acquisition Maximum Ratio Of Debt To EBITDA After Acquisition Maximum Ratio Of Debt To EBITDA permitted under covenants for the fiscal quarter and the two following fiscal quarters after an acquisition. Maximum ratio of debt to capitalization Maximum Ratio Of Debt To Capitalization The maximum ratio of debt to capitalization (defined as net worth plus debt) permitted under the covenants. Acquisition Trigger Amount Acquisition Trigger Amount Aggregate amount of acquisitions that will result in a temporary change in the Debt to EBITDA ratio requirement. Disaggregation of Revenue [Table Text Block] Disaggregation of Revenue [Table Text Block] Contract with Customer, Asset and Liability [Table Text Block] Contract with Customer, Asset and Liability [Table Text Block] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Fair Value Assets and Liabilities Measured On Recurring Basis [Table Text Block] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Fair Value Measurements, Nonrecurring [Table Text Block] Fair Value Measurements, Nonrecurring [Table Text Block] Concentration of receivables, net of allowances, by product or service [Table Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Equity Method Investee [Member] Equity Method Investee [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Product costs Related Party Transaction, Purchases from Related Party Accounts payable Accounts Payable, Related Parties, Current OperatingFeesAndCostsBilledToThirdParty OperatingFeesAndCostsBilledToThirdParty OperatingFeesAndCostsBilledToThirdParty-include operational management fees and expenses billed/rebilled to third party (usually an operated EMI) Schedule of Subsidiary of Limited Liability Company or Limited Partnership [Table] Schedule of Subsidiary of Limited Liability Company or Limited Partnership [Table] WPZ Merger Agreement [Member] Common Stock [Member] Subsidiary, Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock, Name of Transaction [Domain] Sale of Stock [Domain] Dividend Reinvestment Program [Member] Dividend Reinvestment Program [Member] Dividend Reinvestment Program [Member] Financial Repositioning [Member] Financial Repositioning [Member] Financial Repositioning [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Primary Beneficiary [Member] Variable Interest Entity, Primary Beneficiary [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Name of Property [Axis] Name of Property [Axis] Name of Property [Domain] Name of Property [Domain] Conway Fractionator [Member] Conway Fractionator [Member] Conway Fractionator [Member] Geismar [Member] Geismar [Member] -- None. No documentation exists for this element. -- Gulfstar One [Member] Gulfstar One [Member] Gulfstar One, the primary beneficiary of a variable interest entity. Constitution Pipeline Company LLC [Member] Constitution Pipeline Company LLC [Member] Constitution Pipeline Company LLC, the primary beneficiary of a variable interest entity. Cardinal Gas Services LLC [Member] Cardinal Gas Services LLC [Member] Cardinal Gas Services LLC [Member] Appalachia Midstream Services, LLC [Member] Appalachia Midstream Services, LLC [Member] Appalachia Midstream Services, LLC [Member] Northeast JV [Member] Northeast JV [Member] Northeast JV [Member] Schedule of Equity Method Investment, Equity Method Investee, Name [Axis] Equity Method Investee, Name [Domain] Gulfstream Natural Gas System, LLC [Member] Gulfstream Natural Gas System, LLC [Member] Gulfstream Natural Gas System, LLC [Member] Discovery Producer Services LLC [Member] Discovery Producer Services LLC [Member] Discovery Producer Services LLC [Member] Laurel Mountain Midstream, LLC [Member] Laurel Mountain Midstream, LLC [Member] Laurel Mountain Midstream, LLC [Member] Caiman Energy II [Member] Caiman Energy II [Member] Caiman Energy II [Member] Overland Pass Pipeline Company LLC [Member] Overland Pass Pipeline Company LLC [Member] Overland Pass Pipeline Company LLC [Member] Rocky Mountain Midstream Holdings LLC [Member] Rocky Mountain Midstream Holdings LLC [Member] Rocky Mountain Midstream Holdings LLC [Member] Brazos Permian II, LLC [Member] Brazos Permian II LLC [Member] Brazos Permian II LLC [Member] Delaware Basin Gas Gathering System [Member] Delaware Basin Gas Gathering System [Member] Delaware Basin Gas Gathering System [Member] Subsidiary of Limited Liability Company or Limited Partnership [Line Items] Subsidiary of Limited Liability Company or Limited Partnership [Line Items] General and Description Of Business [Abstract] Description Of Business [Abstract] Description Of Business [Abstract] Limited Partners' Capital Account, Units Outstanding Limited Partners' Capital Account, Units Outstanding Stock Issued During Period, Value, New Issues Other Assets, Noncurrent Increase (Decrease) in Other Noncurrent Assets Deferred Tax Liabilities, Net, Noncurrent Increase (Decrease) in Deferred Income Taxes Sale of Stock, Consideration Received on Transaction Sale of Stock, Consideration Received on Transaction Master limited partnership, general partner ownership percentage Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest Sale Of Stock Number Of Shares Issued In Transaction Sale of Stock, Number of Shares Issued in Transaction Payments to Acquire Limited Partnership Interests Payments to Acquire Limited Partnership Interests Sale of Stock, Price Per Share Sale of Stock, Price Per Share Variable Interest Entity Ownership Percentage Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Equity Method Investment, Ownership Percentage Equity Method Investment, Ownership Percentage Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest Basis Of Presentation [Abstract] Basis Of Presentation [Abstract] Basis Of Presentation [Abstract] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Four Corners [Member] Four Corners [Member] Four Corners [Member] Williams Olefins, LLC [Member] Williams Olefins, LLC [Member] Williams Olefins, LLC, a wholly-owned subsidiary of WPZ, which owns interest in the Geismar, Louisiana, olefins plant [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Disposal Groups, Including Discontinued Operations [Table Text Block] Disposal Groups, Including Discontinued Operations [Table Text Block] Provision (Benefit) for Income Taxes [Text Block] Income Tax Disclosure [Text Block] Tax Period [Axis] Tax Period [Axis] Tax Period [Domain] Tax Period [Domain] Unrecognized Tax Benefits that Would Impact Effective Tax Rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Balance at beginning of period Unrecognized Tax Benefits Additions for tax positions of prior years Unrecognized Tax Benefits, Period Increase (Decrease) Balance at end of period Schedule of Regulatory Assets [Table] Schedule of Regulatory Assets [Table] Nonoperating Income (Expense) [Member] Nonoperating Income (Expense) [Member] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Axis] Parties To Contractual Arrangement [Domain] Parties To Contractual Arrangement [Domain] Parties to contractual arrangement. Land [Member] Land [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2016-02 [Member] Accounting Standards Update 2016-02 [Member] Regulatory Assets and Liabilities [Line Items] Regulatory Assets [Line Items] Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Regulatory Charges Resulting From Tax Reform Regulatory Assets and Liabilities Disclosure [Abstract] Regulatory Assets and Liabilities Disclosure [Abstract] Regulatory Assets, Current Regulatory Assets, Current Regulatory Assets, Noncurrent Regulatory Assets, Noncurrent Total regulatory assets Regulatory Assets Regulatory Liabilities, Current Regulatory Liability, Current Regulatory Liabilities, Noncurrent Regulatory Liability, Noncurrent Total regulatory liabilities Regulatory Liabilities Leases [Abstract] Lessee, Operating Lease, Term of Contract Lessee, Operating Lease, Term of Contract Operating Lease, Liability Operating Lease, Liability Operating Lease, Right-of-Use Asset Operating Lease, Right-of-Use Asset Interest Capitalized [Abstract] Capitalized Interest Costs, Including Allowance for Funds Used During Construction [Abstract] Minimum period of construction for capitalization of interest Minimum period of construction for capitalization of interest Minimum period of construction for capitalization of interest. Minimum total project cost for capitalization of interest Minimum total project cost for capitalization of interest Minimum total project cost for capitalization of interest. Retirement Benefits, Description [Abstract] Retirement Benefits, Description [Abstract] Threshold For Amortization Of Unrecognized Actuarial Gains Losses Threshold For Amortization Of Unrecognized Actuarial Gains Losses Threshold For Amortization Of Unrecognized Actuarial Gains Losses, stated as a percentage of the greater of the benefit obligation or the market-related value of plan assets. Approximate Amortization Period Of Net Actuarial Gain Loss Approximate Amortization Period Of Net Actuarial Gain Loss1 Amortization period of net actuarial gain (loss) which is approximately the participants' average remaining future years of service. Amortization Period Of Difference Between Expected And Actual Return On Plan Assets Amortization Period Of Difference Between Expected And Actual Return On Plan Assets Amortization Period Of Difference Between Expected And Actual Return On Plan Assets for calculation of market-related value of plan assets Threshold For Market Related Value Threshold For Market Related Value Threshold For Market Related Value stated as a percentage of the fair value of plan assets as measured at the beginning of the year Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Operating Leases, Rent Expense Operating Leases, Rent Expense Operating Lease, Cost Operating Lease, Cost Short-term Lease, Cost Short-term Lease, Cost Variable Lease, Cost Variable Lease, Cost Sublease Income Sublease Income Lease, Cost Lease, Cost Operating Lease, Payments Operating Lease, Payments Operating Lease, Liability, Current Operating Lease, Liability, Noncurrent Operating Lease, Liability, Noncurrent Operating Lease, Weighted Average Remaining Lease Term Operating Lease, Weighted Average Remaining Lease Term Operating Lease, Weighted Average Discount Rate, Percent Operating Lease, Weighted Average Discount Rate, Percent Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months Lessee, Operating Lease, Liability, Payments, Due Year Two Lessee, Operating Lease, Liability, Payments, Due Year Two Lessee, Operating Lease, Liability, Payments, Due Year Three Lessee, Operating Lease, Liability, Payments, Due Year Three Lessee, Operating Lease, Liability, Payments, Due Year Four Lessee, Operating Lease, Liability, Payments, Due Year Four Lessee, Operating Lease, Liability, Payments, Due Year Five Lessee, Operating Lease, Liability, Payments, Due Year Five Lessee, Operating Lease, Liability, Payments, Due after Year Five Lessee, Operating Lease, Liability, Payments, Due after Year Five Lessee, Operating Lease, Liability, Payments, Due Lessee, Operating Lease, Liability, Payments, Due Lessee, Operating Lease, Liability, Undiscounted Excess Amount Lessee, Operating Lease, Liability, Undiscounted Excess Amount Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Maturities of Long-term Debt [Table Text Block] Schedule of Maturities of Long-term Debt [Table Text Block] Schedule of Line of Credit Facilities [Table Text Block] Schedule of Line of Credit Facilities [Table Text Block] Schedule of Goodwill [Table Text Block] Schedule of Goodwill [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table Text Block] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Performance Obligation Source [Axis] Performance Obligation Source [Axis] Performance Obligation Source [Axis] Performance Obligation Source [Domain] Performance Obligation Source [Domain] [Domain] for Performance Obligation Source [Axis] Performance Obligations Related To Contract Liabilities [Member] Performance Obligations Related To Contract Liabilities [Member] Performance Obligations Related To Contract Liabilities [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Contract with Customer, Liability Contract with Customer, Liability Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Accrued Liabilities [Table Text Block] Schedule of Accrued Liabilities [Table Text Block] Remaining Performance Obligations [Member] Remaining Performance Obligations [Member] Remaining Performance Obligations [Member] Acquisitions and Divestitures [Text Block] Mergers, Acquisitions and Dispositions Disclosures [Text Block] Risks and Uncertainties [Abstract] Risks and Uncertainties [Abstract] Concentration Risk [Table] Concentration Risk [Table] Product and Service [Axis] Products And Services [Domain] NGLs, natural gas, and related products and services [Member] Sale Of NGL And Related Products And Services [Member] Sale of NGL and Related Products and Services [Member] Transportation of natural gas and related products [Member] Transportation of natural gas and related products [member] -- None. No documentation exists for this element. -- Accounts Receivable related to revenues from contracts with customers [Member] Accounts Receivable Related To Contracts With Customers [Member] Accounts Receivable Related To Contracts With Customers [Member] Other Receivable [Member] Other Receivable [Member] Other receivables. Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Chesapeake Energy Corporation [Member] Chesapeake Energy Corporation [Member] Customer One [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Customer Concentration Risk [Member] Customer Concentration Risk [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Revenue Benchmark [Member] Revenue Benchmark [Member] Accounts receivable [Member] Accounts Receivable [Member] Concentration Risk [Line Items] Concentration Risk [Line Items] Trade accounts and other receivables Consolidated revenue, major customer, percentage Concentration Risk, Percentage Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Reclassifications Out Of Accumulated Other Comprehensive Income [Table Text Block] Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Contractual customer relationships [Member] Customer Relationships [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets, Gross Finite-Lived Intangible Assets, Gross Finite-Lived Intangible Assets, Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Acquired Finite-lived Intangible Asset, Weighted-Average Period before Renewal or Extension Acquired Finite-lived Intangible Asset, Weighted-Average Period before Renewal or Extension Amortization of Intangible Assets Amortization of Intangible Assets Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Finite-Lived Intangible Assets, Amortization Expense, Year Two Finite-Lived Intangible Assets, Amortization Expense, Year Two Finite-Lived Intangible Assets, Amortization Expense, Year Three Finite-Lived Intangible Assets, Amortization Expense, Year Three Finite-Lived Intangible Assets, Amortization Expense, Year Four Finite-Lived Intangible Assets, Amortization Expense, Year Four Finite-Lived Intangible Assets, Amortization Expense, Year Five Finite-Lived Intangible Assets, Amortization Expense, Year Five Debt and Banking Arrangements [Text Block] Debt Disclosure [Text Block] Change in benefit obligation: Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Benefit obligation at beginning of year Defined Benefit Plan, Benefit Obligation Interest cost Plan participants’ contributions Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Net actuarial loss (gain) Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Settlements Defined Benefit Plan, Benefit Obligation, Payment for Settlement Net increase (decrease) in benefit obligation Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease) Benefit obligation at end of year Statement of Cash Flows [Abstract] Scenario [Axis] Scenario [Axis] Scenario [Domain] Scenario [Domain] OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile to net cash provided (used) by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Provision (benefit) for deferred income taxes Deferred Income Tax Expense Benefit From Continuing And Discontinued Operations The component of income tax expense for the period representing the increase (decrease) in the entity's deferred tax assets and liabilities pertaining to continuing and discontinued operations. Equity (earnings) losses Distributions from unconsolidated affiliates Proceeds from Equity Method Investment, Distribution Gain on disposition of equity-method investments (Note 6) Equity Method Investment, Realized Gain (Loss) on Disposal Impairment of equity-method investments (Note 18) Equity Method Investment, Other than Temporary Impairment (Gain) on sale of certain assets and businesses (Note 3) Impairment of certain assets (Note 18) Asset Impairment Charges (Gain) loss on deconsolidation of businesses (Note 6) Deconsolidation, Revaluation of Retained Investment, Gain (Loss), Amount Amortization of stock-based awards Share-based Payment Arrangement, Noncash Expense Regulatory charges resulting from Tax Reform (Note 1) Cash provided (used) by changes in current assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts and notes receivable Increase (Decrease) in Accounts and Notes Receivable Inventories Increase (Decrease) in Inventories Other current assets and deferred charges Increase (Decrease) in Other Current Assets Accounts payable Increase (Decrease) in Accounts Payable Accrued liabilities Increase (Decrease) in Accrued Liabilities Other, including changes in noncurrent assets and liabilities Other Operating Activities, Cash Flow Statement Net cash provided (used) by operating activities Net Cash Provided by (Used in) Operating Activities FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from (payments of) commercial paper – net Proceeds from (Repayments of) Commercial Paper Proceeds from long-term debt Proceeds from Issuance of Long-term Debt Payments of long-term debt Repayments of Long-term Debt Proceeds from issuance of common stock Proceeds from sale of partial interest in consolidated subsidiary (Note 3) Proceeds from Divestiture of Interest in Consolidated Subsidiaries Common dividends paid Payments of Ordinary Dividends, Common Stock Dividends and distributions paid to noncontrolling interests Payments of Ordinary Dividends, Noncontrolling Interest Contributions from noncontrolling interests Proceeds from Noncontrolling Interests Payments for debt issuance costs Payments of Debt Issuance Costs Other – net Proceeds from (Payments for) Other Financing Activities Net cash provided (used) by financing activities Net Cash Provided by (Used in) Financing Activities INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Capital expenditures Payments to Acquire Property, Plant, and Equipment Dispositions – net Payments for (Proceeds from) Productive Assets Contributions in aid of construction Proceeds from Contribution in Aid of Construction Proceeds from sale of businesses, net of cash divested Proceeds from Divestiture of Businesses, Net of Cash Divested Purchases of businesses, net of cash acquired (Note 3) Payments to Acquire Businesses, Net of Cash Acquired Proceeds from dispositions of equity-method investments (Note 6) Proceeds from Sale of Equity Method Investments Purchases of and contributions to equity-method investments (Note 6) Payments to Acquire Equity Method Investments Other – net Payments for (Proceeds from) Other Investing Activities Net cash provided (used) by investing activities Net Cash Provided by (Used in) Investing Activities Increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of year Cash and cash equivalents at end of year (1) Increases to property, plant, and equipment Property, Plant and Equipment, Additions Changes in related accounts payable and accrued liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilitiesRelatedToCapitalExpendituresIncurredButNotYetPaid The increase / decrease during the reporting period in future cash outflows to pay for purchases of fixed assets that have occurred. Utica East Ohio Midstream, LLC [Member] Utica East Ohio Midstream, LLC [Member] Utica East Ohio Midstream, LLC [Member] Fair Value, Nonrecurring [Member] Fair Value, Nonrecurring [Member] Impairment Of Equity-Method Investments [Member] Impairment Of Equity-Method Investments [Member] Impairment Of Equity-Method Investments [Member] Pro Forma [Member] Pro Forma [Member] Noncontrolling Interests [Member] Capital in excess of par value [Member] Business Acquisition, Percentage of Voting Interests Acquired Business Acquisition, Percentage of Voting Interests Acquired Payments to Acquire Businesses, Gross Payments to Acquire Businesses, Gross Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss), Net Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss), Net Goodwill, Purchase Accounting Adjustments Goodwill, Purchase Accounting Adjustments Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Business Acquisition, Goodwill, Expected Tax Deductible Amount Business Acquisition, Goodwill, Expected Tax Deductible Amount Percentage Of Finite Lived Intangible Assets Impacted By Our Intent Or Ability To Renew Or Extend Arrangement Percentage Of Finite Lived Intangible Assets Impacted By Our Intent Or Ability To Renew Or Extend Arrangement Percentage of finite-lived intangible assets impacted by our intent or ability to renew or extend arrangement. Business Acquisition, Pro Forma Revenue Business Acquisition, Pro Forma Revenue Business Acquisition, Pro Forma Net Income (Loss) Business Acquisition, Pro Forma Net Income (Loss) Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Business Combination, Acquisition Related Costs Business Combination, Acquisition Related Costs Noncontrolling Interest in Joint Ventures Noncontrolling Interest in Joint Ventures Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Increase (Decrease) in Deferred Income Taxes Leases [Text Block] Lessee, Operating Leases [Text Block] Goodwill and Other Intangible Assets [Text Block] Goodwill and Intangible Assets Disclosure [Text Block] Other Income and Expenses [Text Block] Other Income and Other Expense Disclosure [Text Block] Property, Plant, and Equipment [Text Block] Property, Plant and Equipment Disclosure [Text Block] Changes in benefit obligations and plan assets [Table Text Block] Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan [Table Text Block] Overfunded (underfunded) status of our pension plans and other postretirement benefit plans [Table Text Block] Schedule of Amounts Recognized in Balance Sheet [Table Text Block] Defined Benefit Plan, Plan with Projected Benefit Obligation in Excess of Plan Assets [Table Text Block] Defined Benefit Plan, Plan with Projected Benefit Obligation in Excess of Plan Assets [Table Text Block] Pre-tax amounts not yet recognized in net periodic benefit cost (credit)[Table Text Block] Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block] Schedule of Net Benefit Cost (Credit) [Table Text Block] Schedule of Net Benefit Costs [Table Text Block] Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss) [Table Text Block] Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Schedule of Regulatory Assets / Liabilities [Table Text Block] Schedule of Regulatory Assets [Table Text Block] Defined Benefit Plan, Assumptions [Table Text Block] Defined Benefit Plan, Assumptions [Table Text Block] Fair values of plan assets [Table Text Block] Schedule of Allocation of Plan Assets [Table Text Block] Expected benefit payments [Table Text Block] Schedule of Expected Benefit Payments [Table Text Block] Contract with Customer, Asset, Net - Beginning of Period Contract with Customer, Asset, after Allowance for Credit Loss Contract with Customer, Asset, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress Contract with Customer, Asset, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress Contract with Customer, Asset, Reclassified to Receivable Contract with Customer, Asset, Reclassified to Receivable Contract with Customer, Asset, Net - End of Period Aggregate minimum maturities of long-term debt Long-term Debt, Fiscal Year Maturity [Abstract] 2020 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2021 Long-term Debt, Maturities, Repayments of Principal in Year Two 2022 Long-term Debt, Maturities, Repayments of Principal in Year Three 2023 Long-term Debt, Maturities, Repayments of Principal in Year Four 2024 Long-term Debt, Maturities, Repayments of Principal in Year Five Document and Entity Information [Abstract] -- None. No documentation exists for this element. -- Document Type Document Type Document Annual Report Document Annual Report Document Period End Date Document Period End Date Document Transition Report Document Transition Report Entity File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Public Float Entity Public Float Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Documents Incorporated by Reference [Text Block] Documents Incorporated by Reference [Text Block] Entity Central Index Key Entity Central Index Key Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Schedule of Earnings Per Share [Table] Schedule of Earnings Per Share [Table] Schedule Of Earnings Per Share. Earnings Per Share [Axis] Earnings Per Share [Axis] Earnings Per Share. Earnings Per Share [Domain] Earnings Per Share [Domain] Earnings Per Share. Nonvested restricted stock units [Member] Restricted Stock [Member] Stock options [Member] Earnings Per Share Table [Line Items] Earnings Per Share Table [Line Items] Earnings (loss) per common share Earnings Loss Per Common Share from Continuing Operations [Abstract] Earnings (Loss) Per Common Share from Continuing Operations Basic weighted-average shares Effect of dilutive securities: Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Incremental common shares attributable to share-based payment arrangements under effects of dilutive securities item Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Diluted weighted-average shares Earnings (loss) per common share: Earnings Per Share, Basic and Diluted [Abstract] Earnings (loss) per common share from continuing operations (Textuals) [Abstract] Earnings Loss Per Common Share from Continuing Operations Textuals [Abstract] Earnings (Loss) Per Common Share from Continuing Operations textuals. Number of weighted-average shares excluded from computation of diluted earnings per common share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Earnings (Loss) Per Common Share from Continuing Operations [Text Block] Earnings Per Share [Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Former Alaska Refinery [Member] Former Alaska Refinery [Member] Energy Transfer Merger [Member] Energy Transfer Merger [Member] Energy Transfer Merger [Member] Gas Pipeline [Member] Gas Pipeline [Member] Natural Gas Underground Storage Facilities [Member] Natural Gas Under Ground Storage Facilities [Member] Natural gas underground storage facilities. Former Operations [Member] Former Operations [Member] Former Operations. Unrecorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Unrecorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Capital Addition Purchase Commitments [Member] Capital Addition Purchase Commitments [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Loss Contingency, Damages Awarded, Value Loss Contingency, Damages Awarded, Value Loss contingency, damages sought, value Loss Contingency, Damages Sought, Value Customer Refund Liability, Current Accrued environmental loss liabilities Accrual for Environmental Loss Contingencies Commitments for construction and acquisition of property, plant, and equipment Unrecorded Unconditional Purchase Obligation Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Public Utility Regulated or Unregulated Status [Axis] Regulation Status [Axis] Regulated and Unregulated Operation [Domain] Regulated and Unregulated Operation [Domain] Nonregulated [Member] Unregulated Operation [Member] Regulated [Member] Regulated Operation [Member] Property, Plant and Equipment by Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Natural gas gathering and processing facilities [Member] Gas Gathering and Processing Equipment [Member] Natural gas transmission facilities [Member] Gas, Transmission and Distribution Equipment [Member] Construction in Progress [Member] Construction in Progress [Member] Acquisition Adjustment Of Regulated Facilities [Member] Acquisition Adjustment Included In Property Plant And Equipment For Utilities [Member] Acquisition Adjustment Included in Property Plant and Equipment for Utilities [Member] Other Capitalized Property Plant and Equipment [Member] Other Capitalized Property Plant and Equipment [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property, Plant, and Equipment Property, Plant and Equipment, Net [Abstract] Property, plant, and equipment, at cost Property, Plant and Equipment, Gross Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, plant, and equipment - net Property, Plant and Equipment, Useful Life Property, Plant and Equipment, Useful Life Property, Plant, and Equipment, Depreciation Rate Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service Depreciation and amortization expenses Depreciation Property, Plant and Equipment, Plant Acquisition Adjustments for Intangible Utility Plants Public Utilities, Property, Plant and Equipment, Plant Acquisition Adjustments for Intangible Utility Plants Period of straight-line amortization Finite-Lived Intangible Asset, Useful Life Accrued Liabilities [Text Block] Accounts Payable and Accrued Liabilities Disclosure [Text Block] Provision (Benefit) for Income Taxes (Textuals) [Abstract] ProvisionBenefitForIncomeTaxesTextualsAbstract Expiration 2019 To 2023 [Member] Expiration 2020 To 2023 [Member] [Domain] Expiration 2020 To 2023 [Member] [Domain] Federal tax rate before Tax Reform [Member] Federal tax rate after Tax Reform [Member] Foreign income (loss) in Income from continuing operations before income taxes Income (Loss) from Continuing Operations before Income Taxes, Foreign Deferred Tax Assets, Tax Credit Carryforwards Deferred Tax Assets, Tax Credit Carryforwards Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Proceeds from Income Tax Refunds Proceeds from Income Tax Refunds Income Taxes Paid, Net Income Taxes Paid, Net Unrecognized tax benefits Total interest and penalties recognized as part of income tax provision Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense Total interest and penalties accrued as uncertain tax positions Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Measurement Input, Discount Rate [Member] Measurement Input, Discount Rate [Member] Impairment Of Certain Assets [Member] Impairment Of Certain Assets [Member] Impairment Of Certain Assets [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Property, plant, and equipment, net [Member] Property, Plant and Equipment [Member] Assets Held For Sale [Member] Assets Held For Sale1 [Member] Assets Held For Sale1 [Member] - Balance Sheet Location Property Plant And Equipment, Net And Intangible Assets, Net Of Accumulated Amortization [Member] Property Plant And Equipment, Net And Intangible Assets, Net Of Accumulated Amortization [Member] PropertyPlantAndEquipment,NetAndIntangiblesAssetsNetOfAccummulatedAmortization [Member] Investments [Member] Investments [Member] Pennant Midstream, LLC [Member] Pennant Midstream, LLC [Member] Pennant Midstream, LLC [Member] Fair Value Assets Measured On Nonrecurring Basis [Abstract] Fair Value Assets Measured On Nonrecurring Basis [Abstract] Fair Value Assets Measured On Nonrecurring Basis [Abstract] Fair value of property, plant, and equipment Property, Plant, and Equipment, Fair Value Disclosure Assets Held-for-sale, Long Lived, Fair Value Disclosure Assets Held-for-sale, Long Lived, Fair Value Disclosure Property Plant And Equipment And Intangibles, Fair Value Disclosure Property Plant And Equipment And Intangibles, Fair Value Disclosure PropertyPlantAndEquipmentAndIntangibles,FairValueDisclosure Impairment of certain assets Other Asset Impairment Charges Fair value of investment Investments, Fair Value Disclosure Impairment of equity-method investments Property Plant And Equipment And Intangibles Fair Value Inputs Property Plant And Equipment And Intangibles Fair Value Inputs Inputs used in the fair value determination of Property, Plant and Equipment and Intangibles Investments Fair Value Inputs Investments Fair Value Inputs Investments Fair Value Inputs Other Income and Expenses [Table Text Block] Schedule of Other Operating Cost and Expense, by Component [Table Text Block] Compensation Related Costs, General [Text Block] Compensation Related Costs, General [Text Block] Issuances and Retirements [Abstract] Debt Instruments [Abstract] 8.75 Percent Senior Unsecured Notes Due 2020 [Member] 8.75 Percent Senior Unsecured Notes Due 2020 [Member] 8.75 Percent Senior Unsecured Notes Due 2020 [Member] 7.625% Senior Unsecured Notes Due 2019 [Member] 7.625%SeniorUnsecuredNotesDue2019 [Member] 7.625% Senior Unsecured Notes Due 2019 [Member] 6.05% Senior Unsecured Notes Due 2018 [Member] 6.05 Percent Senior Unsecured Notes Due 2018 [Member] 6.05% Senior Unsecured Notes Due 2018 [Member] Extinguishment of Debt, Amount Extinguishment of Debt, Amount Long-term debt face amount Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Appalachia Midstream Investments [Member] Appalachia Midstream Investments [Member] Appalachia Midstream Investments [Member] Ranch Westex JV LLC [Member] Ranch Westex JV LLC [Member] Ranch Westex JV LLC Other [Member] Other Equity Method Investment [Member] Total equity method investments not separately disclosed. Total Equity Method Investment [Member] Total Equity Method Investment [Member] Total equity method investments. Other Income [Member] Other Income [Member] Schedule of Investments [Line Items] Schedule of Investments [Line Items] Impairment of equity-method investments (Note 18) Gain (loss) on deconsolidation of businesses Gain on disposition of equity-method investment Equity-method investment, payments to purchase or contributions Investments, Fair Value Disclosure Proceeds from dispositions of equity-method investments Equity-method investment, difference between carrying amount and underlying equity Equity Method Investment, Difference Between Carrying Amount and Underlying Equity Summarized Financial Position of Equity Method Investments Equity Method Investment, Summarized Financial Information [Abstract] Current assets Equity Method Investment, Summarized Financial Information, Current Assets Noncurrent assets Equity Method Investment, Summarized Financial Information, Noncurrent Assets Current liabilities Equity Method Investment, Summarized Financial Information, Current Liabilities Noncurrent liabilities Equity Method Investment, Summarized Financial Information, Noncurrent Liabilities Summarized Results of Operations of Equity Method Investments Equity Method Investment, Summarized Financial Information, Income Statement [Abstract] Gross revenue Equity Method Investment, Summarized Financial Information, Revenue Operating income Equity Method Investment Summarized Financial Information Operating Income Equity method investment summarized financial information operating income. Net income Equity Method Investment, Summarized Financial Information, Net Income (Loss) Schedule Of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Variable Interest Entities by Classification of Entity [Axis] Cash and cash equivalents [Member] Cash and Cash Equivalents [Member] Trade accounts and other receivables [Member] Other current assets and deferred charges [Member] Other Current Assets [Member] Intangible assets - net of accumulated amortization [Member] Other Intangible Assets [Member] Regulatory assets, deferred charges, and other [Member] Other Noncurrent Assets [Member] Accounts payable [Member] Accounts Payable [Member] Accrued liabilities [Member] Accrued Liabilities [Member] Regulatory liabilities, deferred income, and other [Member] Other Noncurrent Liabilities [Member] Investments [Domain] Investments [Domain] NonControlling Interest Share [Member] NonControlling Interest Share [Member] NonControlling Interest Share [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract] Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract] Variable Interest Entity, Consolidated, Carrying Amount, Assets Variable Interest Entity, Consolidated, Carrying Amount, Assets Variable Interest Entity, Consolidated, Carrying Amount, Liabilities Variable Interest Entity, Consolidated, Carrying Amount, Liabilities Loss on deconsolidation Deconsolidation, Gain (Loss), Amount Current : Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Foreign Current Foreign Tax Expense (Benefit) Total Current Income Tax Expense (Benefit) Deferred: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Total Deferred Income Tax Expense (Benefit) Fair Value Measurements, Guarantees, and Concentration of Credit Risk [Text Block] Fair Value Disclosures [Text Block] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification out of Accumulated Other Comprehensive Income [Member] Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Accumulated Defined Benefit Plans Adjustment [Member] Foreign currency translation [Member] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Amortization of actuarial (gain) loss and net actuarial loss from settlements included in net periodic benefit cost (credit) Income tax benefit Reclassification from AOCI, Current Period, Tax Reclassifications during the period Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Contract with Customer, Liability [Table] Contract with Customer, Liability [Table] Contract with Customer, Liability [Table] Contract With Customer, Liability [Line Items] Contract With Customer, Liability [Line Items] [Line Items] for Contract With Customer, Liability [Table] Contract with Customer, Liability - Beginning of Period Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress ContractLiabilityNoncashInterestExpenseSignificantFinancingObligation ContractLiabilityNoncashInterestExpenseSignificantFinancingObligation ContractLiabilityNoncashInterestExpenseSignificantFinancingObligation Contract With Customer Liability Increase Decrease For Contract Deconsolidated Contract With Customer Liability Increase Decrease For Contract Deconsolidated Contract With Customer Liability Increase Decrease For Contract Deconsolidated Contract with Customer, Liability, Revenue Recognized Contract with Customer, Liability, Revenue Recognized Contract with Customer, Liability - End of Period Gulf Coast Pipeline Systems [Member] Gulf Coast Pipeline Systems [Member] Gulf Coast Pipeline Systems [Member] Fair Value, Inputs, Level 2 [Member] Income Statement and Additional Disclosures by Disposal Groups [Line Items] Disposal Group, Consideration Disposal Group, Including Discontinued Operation, Consideration Income (Loss) from Individually Significant Component Disposed of, Attributable to Parent, before Income Tax [Abstract] Income (Loss) from Individually Significant Component Disposed of or Held-for-sale, Excluding Discontinued Operations, Attributable to Parent, before Income Tax [Abstract] Income (Loss) before Income Taxes of Disposal Group Income (Loss) from Individually Significant Component Disposed of or Held-for-sale, Excluding Discontinued Operations, before Income Tax Income (Loss) before Income Taxes of Disposal Group Attributable to the Williams Companies, Inc. Income (Loss) from Individually Significant Component Disposed of or Held-for-sale, Excluding Discontinued Operations, Attributable to Parent, before Income Tax Gain on sale of certain assets Gain (Loss) on Disposition of Business Gain (Loss) on Disposition of Business Variable Interest Entities [Text Block] Variable Interest Entity Disclosure [Text Block] Accounting Policies [Abstract] Principles of consolidation [Policy Text Block] Consolidation, Policy [Policy Text Block] Equity-method investment basis differences [Policy Text Block] Equity Method Investment Basis Difference Policy [Policy Textblock] The policy for recognizing differences between the cost of an equity method investment and the underlying equity in the net assets of the investee. Use of estimates [Policy Text Block] Use of Estimates, Policy [Policy Text Block] Regulatory accounting [Policy Text Block] Public Utilities, Policy [Policy Text Block] Cash and cash equivalents [Policy Text Block] Cash and Cash Equivalents, Policy [Policy Text Block] Accounts receivable [Policy Text Block] Receivable [Policy Text Block] Inventories [Policy Text Block] Inventory, Policy [Policy Text Block] Property, plant, and equipment [Policy Text Block] Property, Plant and Equipment, Policy [Policy Text Block] Goodwill [Policy Text Block] Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block] Other Intangible Assets [Policy Text Block] Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block] Impairment of property, plant, and equipment, other identifiable intangible assets, and investments [Policy Text Block] Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Contingent liabilities [Policy Text Block] Commitments and Contingencies, Policy [Policy Text Block] Cash flows from revolving credit facilities and commercial paper program [Policy Text Block] Debt, Policy [Policy Text Block] Treasury stock [Policy Text Block] Treasury stock [Policy Text Block] Disclosure of accounting policy for treasury stock. Derivative instruments and hedging activities [Policy Text Block] Derivatives, Policy [Policy Text Block] Revenue recognition [Policy Text Block] Revenue [Policy Text Block] Leases [Policy Text Block] Lessee, Leases [Policy Text Block] Interest capitalized [Policy Text Block] Interest Capitalization, Policy [Policy Text Block] Employee stock-based awards [Policy Text Block] Compensation Related Costs, Policy [Policy Text Block] Pension and other postretirement benefits [Policy Text Block] Pension and Other Postretirement Plans, Policy [Policy Text Block] Income taxes [Policy Text Block] Income Tax, Policy [Policy Text Block] Earnings (loss) per common share [Policy Text Block] Earnings Per Share, Policy [Policy Text Block] New Accounting Pronouncements and Changes in Accounting Principles [Text Block] New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Cash payments for interest (net of amounts capitalized) Interest Paid, Excluding Capitalized Interest, Operating Activities Schedule II - Valuation and Qualifying Accounts [Text Block] SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax Cash flow hedging activities: Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax [Abstract] Pension and other postretirement benefits: Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax [Abstract] Other Comprehensive Income, Amortization Of Defined Benefit Plan Net Prior Service Cost (Credit) In Net Periodic Benefit Cost (Credit), Tax Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax Other Comprehensive Income (Loss), Defined Benefit Plan, Net Actuarial Gain (Loss) Arising During Period, Tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax Other Comprehensive Income Loss, Reclassification Pension And Other Postretirement Benefit Plans Net Gain Loss Included In Net Periodic Benefit Cost (Credit), Tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax