Income Taxes - Reconciliation of Uncertain Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Uncertain tax benefits
Uncertain tax benefits	$ 13	$ 15
Liability for uncertainty in income taxes, noncurrent	14	18
Unrecognized tax benefits, income tax penalties expense	1
Accrued interest and penalties related to unrecognized tax benefits	1	3
Uncertain tax benefits reconciliation
Balance as of January 1	15	15
Increase due to current year positions	4	3
Increase due to acquired balance from Direct Energy	9	0
Settlements, payments and statute closure	(15)	(3)
Uncertain tax benefits as of December 31	$ 13	$ 15