Other Income and Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Selling, general, and administrative expenses and Operating and maintenance expenses [Member] | Transmission And Gulf Of Mexico [Member]
Segment Reporting Information [Line Items]
Cost, Direct Labor	$ (22)
Severance and other related costs		$ 39
Noncash Contribution Expense			$ 0
WPZ Merger			0
Selling, general, and administrative expenses and Operating and maintenance expenses [Member] | Northeast G And P [Member]
Segment Reporting Information [Line Items]
Cost, Direct Labor	(9)
Severance and other related costs		7
Noncash Contribution Expense			0
WPZ Merger			0
Selling, general, and administrative expenses and Operating and maintenance expenses [Member] | West [Member]
Segment Reporting Information [Line Items]
Cost, Direct Labor	(9)
Severance and other related costs		10
Noncash Contribution Expense			0
WPZ Merger			0
Selling, general, and administrative expenses and Operating and maintenance expenses [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Cost, Direct Labor	0
Severance and other related costs		1
Noncash Contribution Expense			35
WPZ Merger			20
Other income (expense) - net [Member] | Transmission And Gulf Of Mexico [Member]
Segment Reporting Information [Line Items]
Allowance for funds used during construction, capitalized cost of equity	15	32	89
Deferred Taxes On Equity Funds Used During Construction [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Allowance for funds used during construction, capitalized cost of equity	$ (13)	$ 9	$ 35