Derivative Instruments and Hedging Activities - Schedule of Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Derivatives, Fair Value [Line Items]
Derivative assets, gross	$ 193	$ 156
Derivative liabilities, gross	(93)	(360)
Gross Amounts of Recognized Assets/Liabilities	100	(204)
Derivative Instruments	0	0
Net Amount	100	(204)
Energy-related commodity contracts
Derivatives, Fair Value [Line Items]
Derivative assets, gross	20	14
Derivative instruments, assets	0	0
Derivative assets, Net amount	20	14
Derivative liabilities, gross	(82)	(333)
Derivative instruments, liabilities	0	0
Derivative liabilities, net amount	(82)	(333)
Gross Amounts of Recognized Assets/Liabilities	(62)	(319)
Derivative Instruments	0	0
Net Amount	(62)	(319)
Interest rate contracts
Derivatives, Fair Value [Line Items]
Derivative assets, gross	173	142
Derivative instruments, assets	0	0
Derivative assets, Net amount	173	142
Derivative liabilities, gross	(11)	(27)
Derivative instruments, liabilities	0	0
Derivative liabilities, net amount	(11)	(27)
Gross Amounts of Recognized Assets/Liabilities	162	115
Derivative Instruments	0	0
Net Amount	$ 162	$ 115