Investment Securities - AFS Securities in an Unrealized Loss Position (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
AFS securities
AFS: Fair value, less than 12 months	$ 6,929	$ 19,172
AFS: Fair value, 12 months or longer	54,768	57,983
AFS: Fair value, total	61,697	77,155
AFS: Gross unrealized losses, less than 12 months	28	69
AFS: Gross unrealized losses, 12 months or longer	3,991	4,041
AFS: Gross unrealized losses, total	4,019	4,110
U.S. Treasury securities
AFS securities
AFS: Fair value, less than 12 months	4,377	14,295
AFS: Fair value, 12 months or longer	30,024	33,458
AFS: Fair value, total	34,401	47,753
AFS: Gross unrealized losses, less than 12 months	17	22
AFS: Gross unrealized losses, 12 months or longer	843	1,081
AFS: Gross unrealized losses, total	860	1,103
U.S. agency securities
AFS securities
AFS: Fair value, less than 12 months	2,332	4,297
AFS: Fair value, 12 months or longer	19,050	18,459
AFS: Fair value, total	21,382	22,756
AFS: Gross unrealized losses, less than 12 months	9	43
AFS: Gross unrealized losses, 12 months or longer	2,717	2,485
AFS: Gross unrealized losses, total	2,726	2,528
Agency CMBS
AFS securities
AFS: Fair value, less than 12 months	0	0
AFS: Fair value, 12 months or longer	5,102	5,415
AFS: Fair value, total	5,102	5,415
AFS: Gross unrealized losses, less than 12 months	0	0
AFS: Gross unrealized losses, 12 months or longer	420	456
AFS: Gross unrealized losses, total	420	456
State and municipal securities
AFS securities
AFS: Fair value, less than 12 months	180	524
AFS: Fair value, 12 months or longer	34	35
AFS: Fair value, total	214	559
AFS: Gross unrealized losses, less than 12 months	1	3
AFS: Gross unrealized losses, 12 months or longer	1	2
AFS: Gross unrealized losses, total	2	5
FFELP student loan ABS:
AFS securities
AFS: Fair value, less than 12 months	40	56
AFS: Fair value, 12 months or longer	558	616
AFS: Fair value, total	598	672
AFS: Gross unrealized losses, less than 12 months	1	1
AFS: Gross unrealized losses, 12 months or longer	10	17
AFS: Gross unrealized losses, total	$ 11	$ 18

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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