Commitments and Contingencies, Asset Retirement Obligations (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		$ 22	[1],[2]	$ 18	[3]
Accretion	[1]	1
Cash Flow Revisions		3	[1],[4]	4	[3],[5],[6]
Ending balance	[1]	26	[7]	22	[2]
Asset Retirement Obligation, Liabilities Incurred		0		0
Asset Retirement Obligation, Liabilities Settled		0		0
Steam, hydro and other production
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		8	[2]	4
Accretion		1
Cash Flow Revisions		0	[4]	4	[5]
Ending balance		9	[7]	8	[2]
Electric Plant Electric Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		5	[2]	5
Accretion		0
Cash Flow Revisions		0	[4]	0	[5]
Ending balance		5	[7]	5	[2]
Natural Gas Plant Gas Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		9	[2]	9
Accretion		0
Cash Flow Revisions		3	[4]	0	[5]
Ending balance		$ 12	[7]	$ 9	[2]

[1] Included in other long-term liabilities balance in the consolidated balance sheet.

[2] There were no ARO amounts incurred or settled in 2020.

[3] Included in other long-term liabilities balance in the consolidated balance sheet.

[4] In 2021, AROs were revised for changes in timing and estimates of cash flows. Changes in gas 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 steam, hydro and other production AROs primarily related to changes in cost estimates for remediation of ash containment facilities.

[6] Included in other long-term liabilities balance in the consolidated balance sheet.

[7] There were no ARO amounts incurred or settled in 2021.