Investment Securities - Gross Unrealized Losses and Fair Values of Investments in Continuous Unrealized Loss Positions (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
AFS securities, Fair Value
Less than 12 months	$ 2,039	$ 28,352
12 months or more	66,725	43,118
Total	68,764	71,470
AFS securities, Unrealized Losses
Less than 12 months	85	3,439
12 months or more	11,806	8,831
Total	11,891	12,270
U.S. Treasury
AFS securities, Fair Value
Less than 12 months	859	2,069
12 months or more	8,841	8,186
Total	9,700	10,255
AFS securities, Unrealized Losses
Less than 12 months	21	49
12 months or more	684	736
Total	705	785
GSE
AFS securities, Fair Value
Less than 12 months	110	180
12 months or more	169	114
Total	279	294
AFS securities, Unrealized Losses
Less than 12 months	7	14
12 months or more	30	22
Total	37	36
Agency MBS - residential
AFS securities, Fair Value
Less than 12 months	888	25,041
12 months or more	52,284	30,050
Total	53,172	55,091
AFS securities, Unrealized Losses
Less than 12 months	47	3,263
12 months or more	9,741	6,889
Total	9,788	10,152
Debt Securities, Held-to-Maturity, Fair Value
Less than 12 months	0	29,369
12 months or more	45,956	18,422
Total	45,956	47,791
Debt Securities, Held-To-Maturity, Unrealized Losses
Less than 12 months	0	5,613
12 months or more	10,002	4,309
Total	10,002	9,922
Agency MBS - commercial
AFS securities, Fair Value
Less than 12 months	116	790
12 months or more	2,176	1,631
Total	2,292	2,421
AFS securities, Unrealized Losses
Less than 12 months	7	92
12 months or more	544	371
Total	551	463
States and political subdivisions
AFS securities, Fair Value
Less than 12 months	66	251
12 months or more	206	20
Total	272	271
AFS securities, Unrealized Losses
Less than 12 months	3	21
12 months or more	18	3
Total	21	24
Non-agency MBS
AFS securities, Fair Value
Less than 12 months	0	0
12 months or more	3,028	3,117
Total	3,028	3,117
AFS securities, Unrealized Losses
Less than 12 months	0	0
12 months or more	789	810
Total	789	810
Other
AFS securities, Fair Value
Less than 12 months	0	21
12 months or more	21	0
Total	21	21
AFS securities, Unrealized Losses
Less than 12 months	0	0
12 months or more	0	0
Total	$ 0	$ 0