Schedule of Power Cost Adjustment Mechanism (Details) - Subsidiaries [Member] $ in Millions		3 Months Ended		12 Months Ended
	Jan. 01, 2017	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability, Interest		$ 1.1	$ 0.3
Under-collection [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability, Amount		(12.9)	10.6	$ 110.1	$ 68.0
Under-collection [Member] | Companys share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability, Amount				35.5	31.3
Under-collection [Member] | Customer's share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability, Amount		$ 0.0	$ 0.0	74.6	36.7
Under-collection [Member] | Customer's share plus interest
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability, Amount				76.1	38.4
Maximum Power | Customer's share plus interest
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability, Amount				$ 20.0	$ 20.0
Range 1 [Member] | Over-collection [Member] | Companys share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	1
Range 1 [Member] | Over-collection [Member] | Customer's share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	0
Range 1 [Member] | Under-collection [Member] | Companys share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	1
Range 1 [Member] | Under-collection [Member] | Customer's share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	0
Range 2 [Member] | Over-collection [Member] | Companys share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	0.35
Range 2 [Member] | Over-collection [Member] | Customer's share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	0.65
Range 2 [Member] | Under-collection [Member] | Companys share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	0.50
Range 2 [Member] | Under-collection [Member] | Customer's share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	0.50
Range 3 [Member] | Over-collection [Member] | Companys share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	0.10
Range 3 [Member] | Over-collection [Member] | Customer's share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	0.90
Range 3 [Member] | Under-collection [Member] | Companys share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	0.10
Range 3 [Member] | Under-collection [Member] | Customer's share [Member]
Regulatory Assets and Liabiliaties [Line Items]
Annual Power Cost Variability	0.90