Commitment and Contingencies AROs (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		$ 2,350		$ 2,280
Amounts Incurred		(107)	[1]	(90)	[2]
Amounts Settled		0		3	[3]
Accretion		116		117
Cash flow revisions		12	[4]	(134)	[5]
Ending balance		2,585	[6]	2,350
Fair Value, Measurements, Recurring | Nuclear Decommissioning Fund [Member] | Estimate of Fair Value Measurement [Member]
Other Commitments [Line Items]
Legally restricted assets, for purposes of funding future nuclear decommissioning		3,256	[7]	2,777	[8]
Electric Plant Nuclear Production Decommissioning
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		1,957		2,068
Amounts Incurred		0	[1]	0	[2]
Amounts Settled	[3]			0
Accretion		99		105
Cash flow revisions		0	[4]	(216)	[5]
Ending balance		2,056	[6]	1,957
Electric Plant Wind Production
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		270		113
Amounts Incurred		(101)	[1]	(90)	[2]
Amounts Settled	[3]			0
Accretion		13		7
Cash flow revisions		0	[4]	60	[5]
Ending balance		384	[6]	270
Electric Plant Steam Production Ash Containment
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		67		47
Amounts Incurred		(6)	[1]	0	[2]
Amounts Settled	[3]			3
Accretion		2		2
Cash flow revisions		(2)	[4]	21	[5]
Ending balance		73	[6]	67
Electric Plant Electric Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		16		15
Amounts Incurred		0	[1]	0	[2]
Amounts Settled	[3]			0
Accretion		0		1
Cash flow revisions		0	[4]	0	[5]
Ending balance		16	[6]	16
Electric Plant Other
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		0		0
Amounts Incurred	[2]			0
Amounts Settled	[3]			0
Accretion				0
Cash flow revisions	[5]			0
Ending balance				0
Natural Gas Plant Gas Transmission and Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		39		36
Amounts Incurred		0	[1]	0	[2]
Amounts Settled	[3]			0
Accretion		2		2
Cash flow revisions		14	[4]	1	[5]
Ending balance		55	[6]	39
Common and Other Property Common Miscellaneous
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		1		1
Amounts Incurred		0	[1]	0	[2]
Amounts Settled	[3]			0
Accretion		0		0
Cash flow revisions		0	[4]	0	[5]
Ending balance		$ 1	[6]	$ 1

[1] Amounts incurred relate to the wind farms placed in service in 2021 (Blazing Star 2, Mower and Freeborn) and removal of a utility scale battery asset.

[2] Amounts incurred relate to the wind farms placed in service in 2020 (Blazing Star 1, Crowned Ridge, Jeffers and Community Wind North).

[3] Amounts settled related to closure of certain ash containment facilities.

[4] In 2021, AROs were revised for changes in timing and estimates of cash flows. Changes in gas transmission and distribution AROs were primarily related to changes in labor rates coupled with increased gas line mileage and number of services.

[5] In 2020, AROs were revised for changes in timing and estimates of cash flows. Revisions in the nuclear AROs were driven by reductions in spent fuel cooling time requirements in the nuclear triennial filing coupled with decreasing interest rates. Changes in wind AROs were driven by new dismantling studies. Revisions in steam and other production AROs primarily related to changes in cost estimates for remediation of ash containment facilities.

[6] There were no ARO amounts settled in 2021.

[7] Reported in nuclear decommissioning fund and other investments on the consolidated balance sheet, which also includes $52 million of rabbi trust assets and miscellaneous investments.

[8] Reported in nuclear decommissioning fund and other investments on the consolidated balance sheet, which also includes $53 million of rabbi trust assets and miscellaneous investments.