Fair Value of Financial Instruments Fair Value Options Quantitative Disclosure (Details) - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Low [Member]
Commodity Contracts
Electricity physical forwards	$ 39.21	$ 35.00
Natural gas financial swaps	2.81	2.71
Financial swaps - electricity	40.00	54.17
High [Member]
Commodity Contracts
Electricity physical forwards	245.00	270.00
Natural gas financial swaps	9.36	24.71
Financial swaps - electricity	209.00	143.70
Weighted Average [Member]
Commodity Contracts
Electricity physical forwards	96.46	101.27
Natural gas financial swaps	4.02	4.42
Financial swaps - electricity	108.12	104.21
Assets [Member]
Commodity Contracts
Electricity physical forwards	44,000,000	52,000,000
Natural gas financial swaps	6,000,000	6,000,000
Financial swaps - electricity	1,000,000	11,000,000
Total commodity contracts	51,000,000	69,000,000
Liabilities [Member]
Commodity Contracts
Electricity physical forwards	69,000,000	93,000,000
Natural gas financial swaps	8,000,000	8,000,000
Financial swaps - electricity	2,000,000	0
Total commodity contracts	$ 79,000,000	$ 101,000,000