Fair Value of Financial Instruments Fair Value Options Quantitative Disclosure (Details) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Low [Member]
Commodity Contracts
Electricity physical forwards	$ 33.00	$ 35.00
Natural gas financial swaps	2.37	2.71
Financial swaps - electricity	52.00	54.17
High [Member]
Commodity Contracts
Electricity physical forwards	149.00	270.00
Natural gas financial swaps	11.43	24.71
Financial swaps - electricity	120.00	143.70
Weighted Average [Member]
Commodity Contracts
Electricity physical forwards	83.49	101.27
Natural gas financial swaps	3.60	4.42
Financial swaps - electricity	91.88	104.21
Assets [Member]
Commodity Contracts
Electricity physical forwards	12,000,000	52,000,000
Natural gas financial swaps	3,000,000	6,000,000
Financial swaps - electricity	1,000,000	11,000,000
Total commodity contracts	16,000,000	69,000,000
Liabilities [Member]
Commodity Contracts
Electricity physical forwards	111,000,000	93,000,000
Natural gas financial swaps	21,000,000	8,000,000
Financial swaps - electricity	1,000,000	0
Total commodity contracts	$ 133,000,000	$ 101,000,000