Regulatory Assets and Liabilities, Regulatory Liabilities (Details) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		$ 4	$ 31
Regulatory Liability, Noncurrent		372	350
Plant Removal Costs
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		0	0
Regulatory Liability, Noncurrent		201	184
Deferred Income Tax Adjustments and TCJA Refunds
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	[1]	0	0
Regulatory Liability, Noncurrent	[1]	152	161
United States Department of Energy Settlement
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		0	12
Regulatory Liability, Noncurrent		14	0
Deferred Electric Production And Natural Gas Costs
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		3	17
Regulatory Liability, Noncurrent		0	1
Other
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		1	2
Regulatory Liability, Noncurrent		$ 5	$ 4

[1] Includes the revaluation of recoverable/regulated plant accumulated deferred income taxes and revaluation impact of non-plant accumulated deferred income taxes due to the TCJA.