Segment Disclosures Reconciliation of Segment Modified EBITDA to Consolidated Net Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	$ 1,253	$ 1,191	$ 3,552	$ 3,369
Accretion expense associated with asset retirement obligations for nonregulated operations	(8)	(8)	(25)	(26)
Depreciation and amortization expenses	(435)	(425)	(1,275)	(1,290)
Equity earnings (losses)	93	105	260	279
Other investing income (loss) - net	(107)	2	(54)	74
Proportional Modified EBITDA of equity-method investments	(181)	(205)	(546)	(552)
Interest expense	(296)	(270)	(888)	(818)
(Provision) benefit for income taxes	(77)	(190)	(244)	(297)
Net income (loss)	242	200	780	739
Operating Segments [Member] | Northeast G And P [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	345	281	947	786
Operating Segments [Member] | Atlantic Gulf [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	599	492	1,683	1,418
Operating Segments [Member] | West [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	311	412	921	1,214
Operating Segments [Member] | Other [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	$ (2)	$ 6	$ 1	$ (49)