Segment Disclosures Reconciliation of Segment Modified EBITDA to Consolidated Net Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	$ 1,187	$ 1,120
Accretion expense associated with asset retirement obligations for nonregulated operations	(9)	(8)
Depreciation and amortization expenses	(416)	(431)
Equity earnings (losses)	80	82
Equity Method Investment, Other than Temporary Impairment	(74)	0
Other investing income (loss) - net	1	4
Proportional Modified EBITDA of equity-method investments	(190)	(169)
Interest expense	(296)	(273)
(Provision) benefit for income taxes	(69)	(55)
Net income (loss)	214	270
Operating Segments [Member] | Northeast G And P [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	299	250
Operating Segments [Member] | Atlantic Gulf [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	560	451
Operating Segments [Member] | West [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	332	413
Operating Segments [Member] | Other [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	$ (4)	$ 6