Securities - Schedule of Details of Securities (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
SECURITIES AVAILABLE FOR SALE
Amortized Cost	$ 42,945	$ 45,552
Gross Unrealized Gains	0	2
Gross Unrealized Losses	7,106	6,437
Fair Value	35,839	39,117
HELD-TO-MATURITY SECURITIES
Total	8,853	8,710
Gross Unrealized Gains	1	6
Gross Unrealized Losses	810	603
Fair Value	8,044	8,113
Debt securities, available for sale, accrued interest	63	67
Debt securities, held to maturity, accrued interest	25	88
U.S. Treasury, agencies and corporations
SECURITIES AVAILABLE FOR SALE
Amortized Cost	9,466	10,044
Gross Unrealized Gains	0	0
Gross Unrealized Losses	435	629
Fair Value	9,031	9,415
Agency residential collateralized mortgage obligations
SECURITIES AVAILABLE FOR SALE
Amortized Cost	18,822	20,180
Gross Unrealized Gains	0	0
Gross Unrealized Losses	4,162	3,747
Fair Value	14,660	16,433
HELD-TO-MATURITY SECURITIES
Total	5,280	4,586
Gross Unrealized Gains	1	5
Gross Unrealized Losses	449	283
Fair Value	4,832	4,308
Agency residential mortgage-backed securities
SECURITIES AVAILABLE FOR SALE
Amortized Cost	4,294	4,616
Gross Unrealized Gains	0	0
Gross Unrealized Losses	809	696
Fair Value	3,485	3,920
HELD-TO-MATURITY SECURITIES
Total	168	181
Gross Unrealized Gains	0	0
Gross Unrealized Losses	23	16
Fair Value	145	165
Agency commercial mortgage-backed securities
SECURITIES AVAILABLE FOR SALE
Amortized Cost	10,363	10,712
Gross Unrealized Gains	0	2
Gross Unrealized Losses	1,700	1,365
Fair Value	8,663	9,349
HELD-TO-MATURITY SECURITIES
Total	2,511	2,522
Gross Unrealized Gains	0	1
Gross Unrealized Losses	294	208
Fair Value	2,217	2,315
Asset-backed securities
HELD-TO-MATURITY SECURITIES
Total	879	1,407
Gross Unrealized Gains	0	0
Gross Unrealized Losses	43	96
Fair Value	836	1,311
Debt securities, held-to-maturity, purchase of senior notes	871	1,400
Other securities
SECURITIES AVAILABLE FOR SALE
Amortized Cost	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	0	0
HELD-TO-MATURITY SECURITIES
Total	15	14
Gross Unrealized Gains	0	0
Gross Unrealized Losses	1	0
Fair Value	$ 14	$ 14

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