Other Income (Expense), Net (Components of Other Income (Expense), Net) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement [Abstract]
Other income	$ 1	$ 4	$ 3	$ 7
Other expense	0	(18)	1	(16)
Gains on sales of assets	17	0	17	0
Allowance for equity funds used during construction	2	2	3	3
Other income (expense), net	$ 20	$ (12)	$ 24	$ (6)