Investment Securities - Investment Securities (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Available-for-sale debt and other securities:
Total	$ 41,731	$ 43,878
Unrealized Gains	12	6
Unrealized Losses	(3,473)	(4,337)
Fair Value	38,270	39,547
Held-to-maturity securities:
Amortized Cost	11,630	11,278
Unrealized Gains	41	0
Unrealized Losses	(124)	(313)
Fair Value	11,547	10,965
Trading debt securities	1,324	1,185
Equity securities	404	341
Available-for-sale debt securities transferred to held-to-maturity securities
Held-to-maturity securities:
AOCI offset, unamortized portion of unrealized losses on securities	805	865
U.S. Treasury and federal agencies securities
Available-for-sale debt and other securities:
Total	3,505	4,358
Unrealized Gains	3	2
Unrealized Losses	0	0
Fair Value	3,508	4,360
Held-to-maturity securities:
Amortized Cost	2,404	2,370
Unrealized Gains	10	0
Unrealized Losses	0	(26)
Fair Value	2,414	2,344
Agency mortgage-backed securities \| Residential mortgage backed securities
Available-for-sale debt and other securities:
Total	7,515	6,460
Unrealized Gains	4	0
Unrealized Losses	(632)	(779)
Fair Value	6,887	5,681
Held-to-maturity securities:
Amortized Cost	5,238	4,898
Unrealized Gains	8	0
Unrealized Losses	(113)	(197)
Fair Value	5,133	4,701
Agency mortgage-backed securities \| Commercial mortgage-backed securities
Available-for-sale debt and other securities:
Total	23,383	23,853
Unrealized Gains	3	1
Unrealized Losses	(2,443)	(3,022)
Fair Value	20,943	20,832
Held-to-maturity securities:
Amortized Cost	3,986	4,008
Unrealized Gains	23	0
Unrealized Losses	(11)	(90)
Fair Value	3,998	3,918
Non-agency mortgage-backed securities \| Commercial mortgage-backed securities
Available-for-sale debt and other securities:
Total	3,576	4,505
Unrealized Gains	1	0
Unrealized Losses	(254)	(338)
Fair Value	3,323	4,167
Asset-backed securities and other debt securities
Available-for-sale debt and other securities:
Total	2,945	3,924
Unrealized Gains	1	3
Unrealized Losses	(144)	(198)
Fair Value	2,802	3,729
Held-to-maturity securities:
Amortized Cost	2	2
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	2	2
Other securities
Available-for-sale debt and other securities:
Total	807	778
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	807	778
Held-to-maturity securities:
FHLB, restricted stock holdings	300	276
FRB, restricted stock holdings	504	500
DTCC, restricted stock holdings	$ 3	$ 2

AOCI, Debt Securities, Available-for-Sale, Transferred To Held To Maturity, Before Tax

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