Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Balance Sheet) (Parenthetical) (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Related Party Transaction [Line Items]
Derivative assets with affiliates	$ 45	$ 28
Other Current Assets [Member]
Related Party Transaction [Line Items]
Derivative assets with affiliates	11	4
Other Deferred Debits and Other Assets [Member]
Related Party Transaction [Line Items]
Derivative assets with affiliates	$ 34	$ 24