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Securities - Details of Securities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
SECURITIES AVAILABLE FOR SALE
Total	$ 42,695	$ 45,552
Gross Unrealized Gains	10	2
Gross Unrealized Losses	5,520	6,437
Securities available for sale	37,185	39,117
HELD-TO-MATURITY SECURITIES
Total	8,575	8,710
Gross Unrealized Gains	10	6
Gross Unrealized Losses	529	603
Fair Value	$ 8,056	$ 8,113
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Accrued income and other assets	Accrued income and other assets
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Accrued income and other assets	Accrued income and other assets
Available-for-sale securities, accrued interest	$ 64	$ 67
Held-to-maturity securities, accrued interest	25	88
U.S. Treasury, agencies, and corporations
SECURITIES AVAILABLE FOR SALE
Total	9,300	10,044
Gross Unrealized Gains	6	0
Gross Unrealized Losses	280	629
Securities available for sale	9,026	9,415
Agency residential collateralized mortgage obligations
SECURITIES AVAILABLE FOR SALE
Total	18,911	20,180
Gross Unrealized Gains	4	0
Gross Unrealized Losses	3,437	3,747
Securities available for sale	15,478	16,433
HELD-TO-MATURITY SECURITIES
Total	5,170	4,586
Gross Unrealized Gains	9	5
Gross Unrealized Losses	283	283
Fair Value	4,896	4,308
Agency residential mortgage-backed securities
SECURITIES AVAILABLE FOR SALE
Total	4,189	4,616
Gross Unrealized Gains	0	0
Gross Unrealized Losses	600	696
Securities available for sale	3,589	3,920
HELD-TO-MATURITY SECURITIES
Total	165	181
Gross Unrealized Gains	0	0
Gross Unrealized Losses	13	16
Fair Value	152	165
Agency commercial mortgage-backed securities
SECURITIES AVAILABLE FOR SALE
Total	10,295	10,712
Gross Unrealized Gains	0	2
Gross Unrealized Losses	1,203	1,365
Securities available for sale	9,092	9,349
HELD-TO-MATURITY SECURITIES
Total	2,473	2,522
Gross Unrealized Gains	1	1
Gross Unrealized Losses	204	208
Fair Value	2,270	2,315
Asset-backed securities
HELD-TO-MATURITY SECURITIES
Total	738	1,407
Gross Unrealized Gains	0	0
Gross Unrealized Losses	29	96
Fair Value	709	1,311
Securities related to purchase of senior notes	731	1,400
Other securities
SECURITIES AVAILABLE FOR SALE
Total	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Securities available for sale	0	0
HELD-TO-MATURITY SECURITIES
Total	29	14
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 29	$ 14

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