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General, Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies (Details) - USD ($) shares in Millions, $ in Millions		1 Months Ended		6 Months Ended	12 Months Ended
	Aug. 10, 2018	Nov. 30, 2020	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
General and Description Of Business [Abstract]
Stock Issued During Period, Value, New Issues						$ 141	$ (4)
Chesapeake Energy Corporation [Member]
Basis Of Presentation [Abstract]
Property, Plant and Equipment, Gross, Period Increase (Decrease)		$ 98
Increase (Decrease) in Contract with Customer, Liability		67
Increase (Decrease) in Asset Retirement Obligations		$ 31
Gulfstream Natural Gas System, LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					50.00%
Discovery Producer Services LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					60.00%
Laurel Mountain Midstream, LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					69.00%
Overland Pass Pipeline Company LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					50.00%
Rocky Mountain Midstream Holdings LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					50.00%
Blue Racer Midstream LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					50.00%
Williams Companies Inc [Member] \| Northeast JV [Member]
General and Description Of Business [Abstract]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest			65.00%
Transmission And Gulf Of Mexico [Member] \| Gulfstream Natural Gas System, LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					50.00%
Transmission And Gulf Of Mexico [Member] \| Discovery Producer Services LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					60.00%
Transmission And Gulf Of Mexico [Member] \| Williams Companies Inc [Member] \| Gulfstar One [Member]
General and Description Of Business [Abstract]
Variable Interest Entity Ownership Percentage					51.00%
Northeast G And P [Member] \| Laurel Mountain Midstream, LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					69.00%
Northeast G And P [Member] \| Blue Racer Midstream LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					50.00%
Northeast G And P [Member] \| Caiman Energy II [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage						58.00%
Northeast G And P [Member] \| Williams Companies Inc [Member] \| Caiman Energy II [Member]
General and Description Of Business [Abstract]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest					99.00%
Northeast G And P [Member] \| Williams Companies Inc [Member] \| Northeast JV [Member]
General and Description Of Business [Abstract]
Variable Interest Entity Ownership Percentage					65.00%
Northeast G And P [Member] \| Williams Companies Inc [Member] \| Cardinal Gas Services LLC [Member]
General and Description Of Business [Abstract]
Variable Interest Entity Ownership Percentage					66.00%
Northeast G And P [Member] \| Williams Companies Inc [Member] \| Appalachia Midstream Services, LLC [Member]
General and Description Of Business [Abstract]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest					66.00%
West [Member] \| Overland Pass Pipeline Company LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					50.00%
West [Member] \| Rocky Mountain Midstream Holdings LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					50.00%
West [Member] \| Targa Train 7 LLC [Member]
General and Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage					20.00%
West [Member] \| Williams Companies Inc [Member] \| Conway Fractionator [Member]
General and Description Of Business [Abstract]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest					50.00%
West [Member] \| Williams Companies Inc [Member] \| Brazos Permian II, LLC [Member]
Basis Of Presentation [Abstract]
Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest					15.00%
Dividend Reinvestment Program [Member]
General and Description Of Business [Abstract]
Sale of Stock, Consideration Received on Transaction				$ 46
Common Stock [Member]
General and Description Of Business [Abstract]
Stock Issued During Period, Value, New Issues						$ 0	0
Capital in excess of par value [Member]
General and Description Of Business [Abstract]
Stock Issued During Period, Value, New Issues						(426)	14
Accumulated Other Comprehensive Income (Loss)
General and Description Of Business [Abstract]
Stock Issued During Period, Value, New Issues						0	0
Noncontrolling Interests
General and Description Of Business [Abstract]
Stock Issued During Period, Value, New Issues						$ 567	$ (18)
WPZ Merger Agreement [Member]
General and Description Of Business [Abstract]
Limited Partners' Capital Account, Units Outstanding	256
Stock Issued During Period, Shares, New Issues	382
Other Assets, Noncurrent	$ 33
Deferred Tax Liabilities, Net, Noncurrent	(1,829)
WPZ Merger Agreement [Member] \| Common Stock [Member]
General and Description Of Business [Abstract]
Stock Issued During Period, Value, New Issues	382
WPZ Merger Agreement [Member] \| Capital in excess of par value [Member]
General and Description Of Business [Abstract]
Stock Issued During Period, Value, New Issues	6,112
WPZ Merger Agreement [Member] \| Accumulated Other Comprehensive Income (Loss)
General and Description Of Business [Abstract]
Stock Issued During Period, Value, New Issues	(3)
WPZ Merger Agreement [Member] \| Noncontrolling Interests
General and Description Of Business [Abstract]
Stock Issued During Period, Value, New Issues	$ (4,629)