Fair Value of Financial Instruments Fair Value Options Quantitative Disclosure (Details) $ in Millions	Jun. 30, 2026 USD ($) MWh Decatherm	Dec. 31, 2025 USD ($) MWh Decatherm
Minimum [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Electricity physical forward purchase, price per unit \| MWh	7.47	22.99
Natural gas financial swaps, price per unit \| Decatherm	1.49	1.67
Electricity financial futures, price per unit \| MWh	40.42	31
Maximum [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Electricity physical forward purchase, price per unit \| MWh	86.02	94.65
Natural gas financial swaps, price per unit \| Decatherm	3.26	2.76
Electricity financial futures, price per unit \| MWh	77	84
Weighted Average [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Electricity physical forward purchase, price per unit \| MWh	54.87	59.28
Natural gas financial swaps, price per unit \| Decatherm	1.94	2.15
Electricity financial futures, price per unit \| MWh	57.27	52.13
Assets [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Electricity physical forward purchase	$ 0	$ 0
Natural gas financial swaps	0	0
Financial swaps - electricity	5	1
Total commodity contracts	5	1
Liabilities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Electricity physical forward purchase	43	37
Natural gas financial swaps	11	4
Financial swaps - electricity	0	0
Total commodity contracts	$ 54	$ 41