Derivatives and Hedging Activities - Schedule of Cumulative Basis Adjustments on Fair Value Hedges (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivatives, Fair Value [Line Items]
Fair Value	$ 37,298	$ 37,185
Long-term debt | Interest rate
Derivatives, Fair Value [Line Items]
Carrying amount of hedged item	10,738	9,919
Hedge accounting basis adjustment	(566)	(437)
Long-term debt | Interest rate | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Hedge accounting basis adjustment	(5)	(5)
Securities Available for Sale | Interest rate
Derivatives, Fair Value [Line Items]
Carrying amount of hedged item	9,369	8,655
Hedge accounting basis adjustment	20	(152)
Fair Value	12,600	12,800
Hedged layer amount	7,200	7,200
Hedged asset portfolio layer method cumulative basis adjustments	$ 1	$ (147)