Affiliated and Related Party Transactions (Schedule of Affiliated Transactions - Balance Sheet) (Detail) - USD ($) $ in Millions		Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Affiliated and related party payables and other		$ 163	$ 115
Derivative assets with affiliates	[1]	33	51
Related Party | DES
Related Party Transaction [Line Items]
Affiliated and related party payables and other		18	22
Related Party | SCANA Corporation
Related Party Transaction [Line Items]
Affiliated and related party payables and other		7	7
Related Party | Public Service Company Of North Carolina Incorporated
Related Party Transaction [Line Items]
Affiliated and related party payables and other		$ 13	$ 12

[1] Includes amounts recorded in other current assets of $2 million and $8 million as of December 31, 2023 and 2022, respectively, and amounts recorded in other deferred debits and other assets of $31 million and $43 million as of December 31, 2023 and 2022, respectively.