Other Income (Expense), Net (Components of Other Income (Expense), Net) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Operating revenue from contracts with customers	$ 0	$ 1	$ 4
Other income	11	13	19
Other expense	(18)	(38)	(57)
Allowance for equity funds used during construction	5	1	1
Other expense, net	$ (2)	$ (23)	$ (33)