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		$ 112	[1]	$ 77
Amounts Incurred		0		33	[2]
Amounts Settled		0		(2)	[3]
Accretion		4		4
Ending balance		116	[4]	112	[1]
Cash flow revisions		0		0
Electric Plant Steam Production Asbestos
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		52	[1]	51
Amounts Incurred	[2]			0
Amounts Settled	[3]			(2)
Accretion		2		3
Ending balance		54	[4]	52	[1]
Electric Plant Wind Production [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		50	[1]	16
Amounts Incurred	[2]			33
Amounts Settled	[3]			0
Accretion		2		1
Ending balance		52	[4]	50	[1]
Electric Plant Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		10	[1]	10
Amounts Incurred	[2]			0
Amounts Settled	[3]			0
Accretion		0		0
Ending balance		$ 10	[4]	$ 10	[1]

[1] No AROs were revised in 2020.

[2] Amounts incurred related to the Sagamore wind farm placed in service in 2020.

[3] Amounts settled related to asbestos abatement projects.

[4] There were no ARO amounts incurred, settled or revised in 2021.