Regulatory Requirements - U.S. Bank Subsidiaries' Regulatory Capital and Capital Ratios (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Required Ratio
Common Equity Tier 1 capital (as a percent)	13.20%	13.20%
Tier 1 capital (as a percent)	0.147	0.147
Total capital (as a percent)	0.167	0.167
Tier 1 leverage (as a percent)	0.040
SLR (as a percent)	5.00%
Amount
Common Equity Tier 1 capital	$ 67,933	$ 75,742
Tier 1 capital	76,428	83,348
Total capital	$ 86,139	$ 93,166
Ratio
Common Equity Tier 1 capital (as a percent)	0.148	0.160
Tier 1 capital (as a percent)	0.167	0.177
Total capital (as a percent)	0.188	0.197
Tier 1 leverage (as a percent)	0.066	0.071
SLR (as a percent)	0.054	0.056
MSBNA
Well-Capitalized Requirement Ratio [Abstract]
Common Equity Tier 1 capital (as a percent)	6.50%
Tier 1 capital (as a percent)	8.00%
Total capital (as a percent)	0.100
Tier 1 leverage (as a percent)	0.050
SLR (as a percent)	6.00%
Required Ratio
Common Equity Tier 1 capital (as a percent)	7.00%
Tier 1 capital (as a percent)	0.085
Total capital (as a percent)	0.105
Tier 1 leverage (as a percent)	0.040
SLR (as a percent)	3.00%
Amount
Common Equity Tier 1 capital	$ 18,758	$ 18,960
Tier 1 capital	18,758	18,960
Total capital	19,335	19,544
Tier 1 leverage	18,758	18,960
SLR	$ 18,758	$ 18,960
Ratio
Common Equity Tier 1 capital (as a percent)	0.195	0.205
Tier 1 capital (as a percent)	0.195	0.205
Total capital (as a percent)	0.201	0.211
Tier 1 leverage (as a percent)	0.096	0.102
SLR (as a percent)	0.076	0.081
MSPBNA
Well-Capitalized Requirement Ratio [Abstract]
Common Equity Tier 1 capital (as a percent)	6.50%
Tier 1 capital (as a percent)	8.00%
Total capital (as a percent)	0.100
Tier 1 leverage (as a percent)	0.050
SLR (as a percent)	6.00%
Required Ratio
Common Equity Tier 1 capital (as a percent)	7.00%
Tier 1 capital (as a percent)	0.085
Total capital (as a percent)	0.105
Tier 1 leverage (as a percent)	0.040
SLR (as a percent)	3.00%
Amount
Common Equity Tier 1 capital	$ 16,134	$ 10,293
Tier 1 capital	16,134	10,293
Total capital	16,261	10,368
Tier 1 leverage	16,134	10,293
SLR	$ 16,134	$ 10,293
Ratio
Common Equity Tier 1 capital (as a percent)	0.290	0.243
Tier 1 capital (as a percent)	0.290	0.243
Total capital (as a percent)	0.292	0.245
Tier 1 leverage (as a percent)	0.081	0.069
SLR (as a percent)	0.079	0.067