Dispositions (Details) $ in Millions	9 Months Ended
	Sep. 30, 2025 USD ($) MWh	Sep. 30, 2024 USD ($) MWh	Jan. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Mar. 01, 2023 USD ($) MWh project	Oct. 01, 2022 USD ($)
Electric Energy (MWh)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Notional amount | MWh	31,734,340
Broken Bow II | Electric Energy (MWh) | Clean Energy Businesses
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deferred projects | project					1
Notional amount | MWh		75			75
Clean Energy Businesses | RWE | Maximum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimate of possible loss (up to)	$ 172
Disposal Group, Held-for-sale, Not Discontinued Operations | Clean Energy Businesses
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration from sale of business					$ 3,993	$ 6,800
Gain on sale of subsidiary	803	$ 835
Gain on sale of subsidiary, after tax	722	745
Downward price adjustment		30
Downward price adjustment, after tax		$ 22
Disposal Group, Held-for-sale, Not Discontinued Operations | Clean Energy Businesses | Broken Bow II
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration from sale of business			$ 54
Disposal Group, Held-for-sale, Not Discontinued Operations | Crane Project
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Carrying value of tax equity interest	$ 4			$ 4