General, Description of Business, and Basis of Presentation (Details) - USD ($) $ in Millions		3 Months Ended
	Aug. 10, 2018	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Dec. 31, 2018
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Operating Lease, Liability		$ 223
Operating Costs and Expenses		340	$ 357
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net			(2)
Other Nonoperating Income (Expense)		11	21
Operating Income (Loss)		(561)	(491)
Net Cash Provided by (Used in) Operating Activities		775	694
Net Cash Provided by (Used in) Investing Activities		1,258	798
Additional Paid in Capital, Common Stock		24,703			$ 24,693
Other Assets, Noncurrent		962			746
Accumulated Other Comprehensive Income (Loss), Net of Tax		267			270
Stockholders' Equity Attributable to Noncontrolling Interest		(1,319)			(1,337)
Deferred Tax Liabilities, Net, Noncurrent		(1,601)			$ (1,524)
Operating Lease, Right-of-Use Asset		$ 223
Noncontrolling Interest [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net			(9)
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			$ 7
Dividend Reinvestment Program [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Sale of Stock, Number of Shares Issued in Transaction			576,923
Sale of Stock, Consideration Received on Transaction			$ 22
Accounting Standards Update 2016-02 [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Operating Lease, Liability				$ 225
Operating Lease, Right-of-Use Asset				$ 225
WPZ Merger Agreement [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Limited Partners' Capital Account, Units Outstanding	256,000,000
Stock Issued During Period, Shares, New Issues	382,000,000
Stock Issued During Period, Value, New Issues	$ 382
Additional Paid in Capital, Common Stock	6,112
Other Assets, Noncurrent	33
Accumulated Other Comprehensive Income (Loss), Net of Tax	3
Stockholders' Equity Attributable to Noncontrolling Interest	4,629
Deferred Tax Liabilities, Net, Noncurrent	$ 1,829
Northeast G And P [Member] | Cardinal Gas Services LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Variable Interest Entity Ownership Percentage		66.00%
Northeast G And P [Member] | 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%
Atlantic Gulf [Member] | Constitution Pipeline Company LLC [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Variable Interest Entity Ownership Percentage		41.00%
Atlantic Gulf [Member] | Gulfstar One [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Variable Interest Entity Ownership Percentage		51.00%
Conway Fractionator [Member] | West [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest		50.00%
Gulfstream Natural Gas System, L.L.C.[Member] | Atlantic Gulf [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%
Laurel Mountain Midstream, LLC [Member] | Northeast G And P [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		69.00%
Caiman Energy II [Member] | Northeast G And P [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		58.00%
Discovery Producer Services LLC [Member] | Atlantic Gulf [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		60.00%
Overland Pass Pipeline Company LLC [Member] | West [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		50.00%
Jackalope Gas Gathering Services LLC [Member] | West [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		50.00%
Rocky Mountain Midstream Holdings LLC [Member] | West [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		50.00%
Brazos Permian II LLC [Member] | West [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		15.00%