Securities - Schedule of Available for Sale Securities in an Unrealized Loss Position (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Held-to-maturity securities:
Temporarily impaired securities, fair value, less than 12 months	$ 10,587	$ 2,004
Temporarily impaired securities, gross unrealized losses, less than 12 months	97	11
Temporarily impaired securities, fair value, 12 months or longer	20,272	22,705
Temporarily impaired securities, gross unrealized losses, 12 months or longer	2,931	2,836
Temporarily impaired securities, fair value	30,859	24,709
Temporarily impaired securities, gross unrealized losses	3,028	2,847
U.S. Treasury, agencies and corporations
Securities available for sale:
Fair value, less than 12 months	1,675	0
Gross unrealized losses, less than 12 months	6	0
Fair value, 12 months or longer	523	525
Gross unrealized losses, 12 months or longer	20	17
Fair Value	2,198	525
Gross Unrealized Losses	26	17
Agency residential collateralized mortgage obligations
Securities available for sale:
Fair value, less than 12 months	0	0
Gross unrealized losses, less than 12 months	0	0
Fair value, 12 months or longer	7,423	7,677
Gross unrealized losses, 12 months or longer	1,760	1,708
Fair Value	7,423	7,677
Gross Unrealized Losses	1,760	1,708
Held-to-maturity securities:
Fair value, less than 12 months	499	240
Gross unrealized losses, less than 12 months	8	2
Fair value, 12 months or longer	2,814	3,023
Gross unrealized losses, 12 months or longer	196	174
Fair Value	3,313	3,263
Gross Unrealized Losses	204	176
Agency residential mortgage-backed securities
Securities available for sale:
Fair value, less than 12 months	5,860	1,226
Gross unrealized losses, less than 12 months	59	7
Fair value, 12 months or longer	3,951	5,583
Gross unrealized losses, 12 months or longer	448	450
Fair Value	9,811	6,809
Gross Unrealized Losses	507	457
Held-to-maturity securities:
Fair value, less than 12 months	2,437	526
Gross unrealized losses, less than 12 months	22	2
Fair value, 12 months or longer	121	125
Gross unrealized losses, 12 months or longer	12	11
Fair Value	2,558	651
Gross Unrealized Losses	34	13
Agency commercial mortgage-backed securities
Securities available for sale:
Fair value, less than 12 months	109	7
Gross unrealized losses, less than 12 months	2	0
Fair value, 12 months or longer	3,623	3,777
Gross unrealized losses, 12 months or longer	349	335
Fair Value	3,732	3,784
Gross Unrealized Losses	351	335
Held-to-maturity securities:
Fair value, less than 12 months	0	0
Gross unrealized losses, less than 12 months	0	0
Fair value, 12 months or longer	1,771	1,914
Gross unrealized losses, 12 months or longer	145	139
Fair Value	1,771	1,914
Gross Unrealized Losses	145	139
Asset-backed securities
Held-to-maturity securities:
Fair value, less than 12 months	0	0
Gross unrealized losses, less than 12 months	0	0
Fair value, 12 months or longer	43	75
Gross unrealized losses, 12 months or longer	1	2
Fair Value	43	75
Gross Unrealized Losses	1	2
Other securities
Held-to-maturity securities:
Fair value, less than 12 months	7	5
Gross unrealized losses, less than 12 months	0	0
Fair value, 12 months or longer	3	6
Gross unrealized losses, 12 months or longer	0	0
Fair Value	10	11
Gross Unrealized Losses	$ 0	$ 0

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