HTM Debt Securities, Contractual Maturities (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Held-to-Maturity, Amortized Cost Excluding Accrued Interest, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Rolling Maturity [Abstract]
Held-to-maturity, amortized cost, net	$ 300,434	$ 272,022
Held-to-maturity, amortized cost, net, remaining contractual maturity, due within one year	1,860
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after one year through five years	15,247
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after five years through ten years	16,507
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after ten years	266,820
Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value, Rolling Maturity [Abstract]
Held-to-maturity, fair value	255,571	272,386
Held-to-maturity, fair value, remaining contractual maturity, due within one year	1,841
Held-to-maturity, fair value, remaining contractual maturity, due after one year through five years	14,673
Held-to-maturity, fair value, remaining contractual maturity, due after five years through ten years	15,993
Held-to-maturity, fair value, remaining contractual maturity, due after ten years	$ 223,064
Debt Securities, Held-to-Maturity, Rolling Maturity, Weighted Average Yield [Abstract]
Held-to-maturity weighted average yield	2.44%
Held-to-maturity, weighted average yield, remaining contractual maturity, due within one year	1.66%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after one year through five years	2.34%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after five years through ten years	3.97%
Held-to-maturity, weighed average yield, remaining contractual maturity, due after ten years	2.36%
Securities of U.S. Treasury and federal agencies [Member]
Debt Securities, Held-to-Maturity, Amortized Cost Excluding Accrued Interest, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Rolling Maturity [Abstract]
Held-to-maturity, amortized cost, net	$ 16,200	16,544
Held-to-maturity, amortized cost, net, remaining contractual maturity, due within one year	0
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after one year through five years	12,414
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after five years through ten years	0
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after ten years	3,786
Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value, Rolling Maturity [Abstract]
Held-to-maturity, fair value	14,358	16,825
Held-to-maturity, fair value, remaining contractual maturity, due within one year	0
Held-to-maturity, fair value, remaining contractual maturity, due after one year through five years	11,968
Held-to-maturity, fair value, remaining contractual maturity, due after five years through ten years	0
Held-to-maturity, fair value, remaining contractual maturity, due after ten years	$ 2,390
Debt Securities, Held-to-Maturity, Rolling Maturity, Weighted Average Yield [Abstract]
Held-to-maturity weighted average yield	2.18%
Held-to-maturity, weighted average yield, remaining contractual maturity, due within one year	0.00%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after one year through five years	2.37%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after five years through ten years	0.00%
Held-to-maturity, weighed average yield, remaining contractual maturity, due after ten years	1.58%
Securities of U.S. states and political subdivisions [Member]
Debt Securities, Held-to-Maturity, Amortized Cost Excluding Accrued Interest, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Rolling Maturity [Abstract]
Held-to-maturity, amortized cost, net	$ 31,478	32,689
Held-to-maturity, amortized cost, net, remaining contractual maturity, due within one year	1,845
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after one year through five years	2,056
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after five years through ten years	2,100
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after ten years	25,477
Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value, Rolling Maturity [Abstract]
Held-to-maturity, fair value	25,917	33,475
Held-to-maturity, fair value, remaining contractual maturity, due within one year	1,827
Held-to-maturity, fair value, remaining contractual maturity, due after one year through five years	1,977
Held-to-maturity, fair value, remaining contractual maturity, due after five years through ten years	2,022
Held-to-maturity, fair value, remaining contractual maturity, due after ten years	$ 20,091
Debt Securities, Held-to-Maturity, Rolling Maturity, Weighted Average Yield [Abstract]
Held-to-maturity weighted average yield	2.13%
Held-to-maturity, weighted average yield, remaining contractual maturity, due within one year	1.64%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after one year through five years	1.49%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after five years through ten years	2.33%
Held-to-maturity, weighed average yield, remaining contractual maturity, due after ten years	2.20%
Federal agency mortgage-backed securities [Member]
Debt Securities, Held-to-Maturity, Amortized Cost Excluding Accrued Interest, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Rolling Maturity [Abstract]
Held-to-maturity, amortized cost, net	$ 219,739	188,909
Held-to-maturity, amortized cost, net, remaining contractual maturity, due within one year	0
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after one year through five years	0
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after five years through ten years	0
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after ten years	219,739
Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value, Rolling Maturity [Abstract]
Held-to-maturity, fair value	183,705	187,984
Held-to-maturity, fair value, remaining contractual maturity, due within one year	0
Held-to-maturity, fair value, remaining contractual maturity, due after one year through five years	0
Held-to-maturity, fair value, remaining contractual maturity, due after five years through ten years	0
Held-to-maturity, fair value, remaining contractual maturity, due after ten years	$ 183,705
Debt Securities, Held-to-Maturity, Rolling Maturity, Weighted Average Yield [Abstract]
Held-to-maturity weighted average yield	2.26%
Held-to-maturity, weighted average yield, remaining contractual maturity, due within one year	0.00%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after one year through five years	0.00%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after five years through ten years	0.00%
Held-to-maturity, weighed average yield, remaining contractual maturity, due after ten years	2.26%
Non-agency mortgage-backed securities [Member]
Debt Securities, Held-to-Maturity, Amortized Cost Excluding Accrued Interest, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Rolling Maturity [Abstract]
Held-to-maturity, amortized cost, net	$ 1,243	1,082
Held-to-maturity, amortized cost, net, remaining contractual maturity, due within one year	15
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after one year through five years	18
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after five years through ten years	52
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after ten years	1,158
Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value, Rolling Maturity [Abstract]
Held-to-maturity, fair value	1,070	1,095
Held-to-maturity, fair value, remaining contractual maturity, due within one year	14
Held-to-maturity, fair value, remaining contractual maturity, due after one year through five years	17
Held-to-maturity, fair value, remaining contractual maturity, due after five years through ten years	47
Held-to-maturity, fair value, remaining contractual maturity, due after ten years	$ 992
Debt Securities, Held-to-Maturity, Rolling Maturity, Weighted Average Yield [Abstract]
Held-to-maturity weighted average yield	3.08%
Held-to-maturity, weighted average yield, remaining contractual maturity, due within one year	3.24%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after one year through five years	2.93%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after five years through ten years	3.47%
Held-to-maturity, weighed average yield, remaining contractual maturity, due after ten years	3.07%
Collateralized loan obligations [Member]
Debt Securities, Held-to-Maturity, Amortized Cost Excluding Accrued Interest, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Rolling Maturity [Abstract]
Held-to-maturity, amortized cost, net	$ 30,046	31,067
Held-to-maturity, amortized cost, net, remaining contractual maturity, due within one year	0
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after one year through five years	0
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after five years through ten years	13,386
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after ten years	16,660
Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value, Rolling Maturity [Abstract]
Held-to-maturity, fair value	28,958	31,259
Held-to-maturity, fair value, remaining contractual maturity, due within one year	0
Held-to-maturity, fair value, remaining contractual maturity, due after one year through five years	0
Held-to-maturity, fair value, remaining contractual maturity, due after five years through ten years	13,072
Held-to-maturity, fair value, remaining contractual maturity, due after ten years	$ 15,886
Debt Securities, Held-to-Maturity, Rolling Maturity, Weighted Average Yield [Abstract]
Held-to-maturity weighted average yield	4.09%
Held-to-maturity, weighted average yield, remaining contractual maturity, due within one year	0.00%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after one year through five years	0.00%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after five years through ten years	4.17%
Held-to-maturity, weighed average yield, remaining contractual maturity, due after ten years	4.03%
Other debt securities [Member]
Debt Securities, Held-to-Maturity, Amortized Cost Excluding Accrued Interest, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Rolling Maturity [Abstract]
Held-to-maturity, amortized cost, net	$ 1,728	1,731
Held-to-maturity, amortized cost, net, remaining contractual maturity, due within one year	0
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after one year through five years	759
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after five years through ten years	969
Held-to-maturity, amortized cost, net, remaining contractual maturity, due after ten years	0
Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value, Rolling Maturity [Abstract]
Held-to-maturity, fair value	1,563	$ 1,748
Held-to-maturity, fair value, remaining contractual maturity, due within one year	0
Held-to-maturity, fair value, remaining contractual maturity, due after one year through five years	711
Held-to-maturity, fair value, remaining contractual maturity, due after five years through ten years	852
Held-to-maturity, fair value, remaining contractual maturity, due after ten years	$ 0
Debt Securities, Held-to-Maturity, Rolling Maturity, Weighted Average Yield [Abstract]
Held-to-maturity weighted average yield	4.47%
Held-to-maturity, weighted average yield, remaining contractual maturity, due within one year	0.00%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after one year through five years	4.13%
Held-to-maturity, weighted average yield, remaining contractual maturity, due after five years through ten years	4.74%
Held-to-maturity, weighed average yield, remaining contractual maturity, due after ten years	0.00%