Income Taxes (Details)		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Federal statutory rate, percent		21.00%	21.00%
State tax (net of federal tax effect), percent		2.50%	2.60%
Wind PTCs, percent		(87.20%)	(65.50%)
Plant regulatory differences, percent	[1]	(4.00%)	(4.70%)
Other tax credits, percent		(1.10%)	(1.20%)
Other (net), percent		1.10%	(0.90%)
Effective income tax rate, percent		(67.70%)	(48.70%)

[1] Regulatory differences for income tax primarily relate to the credit of excess deferred taxes to customers through the average rate assumption method. Income tax benefits associated with the credit of excess deferred credits are offset by corresponding revenue reductions.