Securities - Securities by Maturity (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Amortized Cost of Securities Available for sale, Due in one year or less	$ 620
Amortized Cost of Securities Available for sale, Due after one through five years	16,918
Amortized Cost of Securities Available for sale, Due after five through ten years	21,439
Amortized Cost of Securities Available for sale, Due after ten years	7,314
Amortized Cost	46,291
Fair Value of Securities Available for sale, Due in one year or less	599
Fair Value of Securities Available for sale, Due after one through five years	15,566
Fair Value of Securities Available for sale, Due after five through ten years	17,962
Fair Value of Securities Available for sale, Due after ten years	5,873
Fair Value	40,000	$ 45,364
Amortized Cost of Held-to-Maturity Securities, Due in one year or less	24
Amortized Cost of Held-to-Maturity Securities, Due after one through five years	4,526
Amortized Cost of Held-to-Maturity Securities, Due after five through ten years	2,500
Amortized Cost of Held-to-Maturity Securities, Due after ten years	1,113
Amortized Cost	8,163	7,539
Fair Value of Held-to-Maturity Securities, Due in one year or less	23
Fair Value of Held-to-Maturity Securities, Due after one through five years	4,203
Fair Value of Held-to-Maturity Securities, Due after five through ten years	2,303
Fair Value of Held-to-Maturity Securities, Due after ten years	1,067
Total Fair Value of Held-to-Maturity Securities	$ 7,596	$ 7,665