General, Description of Business, and Basis of Presentation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions				1 Months Ended						3 Months Ended
	Feb. 10, 2017	Jan. 09, 2017	Sep. 28, 2015	Feb. 10, 2017	Feb. 03, 2017	Jan. 31, 2017	May 31, 2016	Feb. 29, 2016	Nov. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 17, 2017	Jan. 01, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Number Of Interstate Natural Gas Pipelines										2
Equity Method Investments										$ 6,738				$ 6,701
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Common Stock, Dividends, Per Share, Declared										$ 0.30	$ 0.64
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net										$ (901)
Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets													$ 37
WPZ Merger Agreement [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Termination Fee			$ 428
Maximum Reduction Of Quarterly Incentive Distributions			$ 209
Reduction in incentive distribution rights payment							$ 10	$ 209	$ 209
Constitution Pipeline Company LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Variable Interest Entity Ownership Percentage										41.00%
Appalachia Midstream Services, LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest										66.00%
Noncontrolling Interest [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net										$ (2,397)
Capital in excess of par value [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net										1,496
Deferred Income Taxes [Member] | Williams Partners L.P. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net										$ 901
General and Limited Partner [Member] | Williams Partners L.P. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Variable Interest Entity Ownership Percentage			60.00%							74.00%
Limited Partner [Member] | Williams Partners L.P. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Variable Interest Entity Ownership Percentage										74.00%
Financial Repositioning [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Sale of Stock, Number of Shares Issued in Transaction		277			59,000	289,000
Payments to Acquire Limited Partnership Interests	$ 50	$ 10
Sale of Stock, Price Per Share					$ 36.08586
Financial Repositioning [Member] | Williams Partners L.P. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest						2.00%
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest				74.00%
Williams Partners [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Goodwill										$ 47
Gulfstream Natural Gas System, L.L.C.[Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage										50.00%
Utica East Ohio Midstream, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage										62.00%
Delaware Basin Gas Gathering System [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage												50.00%
Delaware Basin Gas Gathering System [Member] | Williams Partners [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage										50.00%
Laurel Mountain Midstream, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage										69.00%
Caiman Energy II [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage										58.00%
Discovery Producer Services LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage										60.00%
Overland Pass Pipeline Company LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage										50.00%