Segment Disclosures Reconciliation of Segment Modified EBITDA to Consolidated Net Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	$ 1,253	$ 1,187
Accretion expense associated with asset retirement obligations for nonregulated operations	(10)	(9)
Depreciation and amortization expenses	(429)	(416)
Impairment of goodwill	(187)	0
Equity earnings (losses)	22	80
Impairment of equity-method investments	938	74
Other investing income (loss) - net	3	1
Proportional Modified EBITDA of equity-method investments	(192)	(190)
Interest expense	(296)	(296)
(Provision) benefit for income taxes	204	(69)
Net income (loss)	(570)	214
Operating Segments [Member] | Transmission And Gulf Of Mexico [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	662	636
Operating Segments [Member] | Northeast G And P [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	369	299
Operating Segments [Member] | West [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	215	256
Operating Segments [Member] | Other [Member]
Reconciliation of Modified EBITDA to Net Income (Loss):
Modified EBITDA Earnings (Loss)	$ 7	$ (4)