Other Accruals (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Segment Reporting Information [Line Items]
Severance and other related costs	$ 43	$ 43
Transmission And Gulf Of Mexico [Member]
Segment Reporting Information [Line Items]
Severance and other related costs	22	22
Northeast G And P [Member]
Segment Reporting Information [Line Items]
Severance and other related costs	10	10
West [Member]
Segment Reporting Information [Line Items]
Severance and other related costs	11	11
Operating Expense [Member]
Segment Reporting Information [Line Items]
Severance and other related costs	23	23
Selling, general, and administrative expenses [Member]
Segment Reporting Information [Line Items]
Severance and other related costs	$ 20	$ 20