Derivatives and Hedging Activities - Gains and Losses (Details) - Interest Rate Contract - Fair Value Hedges - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Derivative Instruments, Gain (Loss) [Line Items]
Fixed-rate long-term debt	$ (89)	$ (554)	$ (488)	$ (481)
Derivatives designated as hedging instruments	89	550	489	476
Total	$ 1	$ (4)	$ 1	$ (5)