Investment Securities - Proceeds and Gross Realized Gains and Losses from Sales of Securities Available for Sale (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Proceeds	[1]	$ 8,465	$ 24,704	$ 13,306
Gross realized gains		1	157	40
Gross realized losses		$ 62	$ 166	$ 36

[1] Certain prior year amounts have been reclassified to conform to the current year presentation. See Note 1 for additional information.