Derivative Instruments and Hedging Activities - Hedged Items in Fair Value Hedging Relationship (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Hedged Items In Fair Value Hedging Relationship [Line Items]
Total Assets	$ 33	$ (13)
Discontinued Hedging Relationships, Assets	2,200	236
Designated hedged items	1,500	225
Investment securities available for sale
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount Assets	6,108	3,983
Total Assets	(8)	(80)
Discontinued Hedging Relationships, Assets	126	200
Interest-bearing deposits
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount Liabilities	(17,374)	(17,280)
Total Liabilities	277	500
Discontinued Hedging Relationships, Liabilities	0	(1)
Securitized debt obligations
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount Liabilities	(13,375)	(11,921)
Total Liabilities	503	748
Discontinued Hedging Relationships, Liabilities	0	0
Senior and subordinated notes
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount Liabilities	(30,899)	(24,544)
Total Liabilities	971	1,542
Discontinued Hedging Relationships, Liabilities	$ (372)	$ (527)