Securities - Schedule of Securities by Maturity (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Securities Available for Sale, Amortized Cost
Due in one year or less	$ 6,340
Due after one through five years	10,773
Due after five through ten years	18,425
Due after ten years	7,551
Total	43,089
Securities Available for Sale, Fair Value
Due in one year or less	6,247
Due after one through five years	10,052
Due after five through ten years	15,300
Due after ten years	5,861
Total	37,460	$ 37,185
Held-to-Maturity Securities, Amortized Cost
Due in one year or less	512
Due after one through five years	3,427
Due after five through ten years	2,806
Due after ten years	1,223
Total	7,968	8,575
Held-to-Maturity Securities, Fair Value
Due in one year or less	499
Due after one through five years	3,194
Due after five through ten years	2,543
Due after ten years	1,122
Total	$ 7,358	$ 8,056