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, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]
Fixed-rate long-term debt	$ 937	$ (89)	$ 1,529	$ (488)
Derivatives designated as hedging instruments	(938)	89	(1,530)	489
Total	$ (1)	$ 1	$ (1)	$ 1