Risk Management - Effect on Income Statement Not Designated (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Derivative [Line Items]
Gain/(loss) recognized in income on derivatives	$ (5)	$ (20)	$ (105)	$ (26)
Energy commodity derivative contracts \| Statement of Income Location Balance [Axis]: us-gaap:CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization
Derivative [Line Items]
Gain/(loss) recognized in income on derivatives	11	(25)	(113)	(45)
Energy commodity derivative contracts \| Statement of Income Location Balance [Axis]: us-gaap:IncomeLossFromEquityMethodInvestments
Derivative [Line Items]
Gain/(loss) recognized in income on derivatives	1	1	2	1
Energy commodity derivative contracts \| Statement of Income Location Balance [Axis]: us-gaap:Revenues
Derivative [Line Items]
Gain/(loss) recognized in income on derivatives	(17)	6	6	22
Interest rate contracts \| Statement of Income Location Balance [Axis]: us-gaap:InterestIncomeExpenseNonoperatingNet
Derivative [Line Items]
Gain/(loss) recognized in income on derivatives	0	(2)	0	(4)
Derivative Contracts Settled
Derivative [Line Items]
Gain/(loss) recognized in income on derivatives	$ 7	$ (4)	$ (82)	$ (20)