Other Accruals (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Segment Reporting Information [Line Items]
Severance and other related costs	$ 10	$ 53
Transmission And Gulf Of Mexico [Member]
Segment Reporting Information [Line Items]
Severance and other related costs	14	36
Northeast G And P [Member]
Segment Reporting Information [Line Items]
Severance and other related costs	(3)	7
West [Member]
Segment Reporting Information [Line Items]
Severance and other related costs	(1)	10
Operating Expense [Member]
Segment Reporting Information [Line Items]
Severance and other related costs	7	30
Selling, general, and administrative expenses [Member]
Segment Reporting Information [Line Items]
Severance and other related costs	$ 3	$ 23