Regulatory Requirements (U.S. Bank Subsidiaries' Regulatory Capital and Capital Ratios) (Details) - Standardized Approach Transitional Rules - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Amount
Common Equity Tier 1 capital	$ 60,568	$ 61,134
Tier 1 capital	69,213	69,938
Total capital	79,363	80,275
Tier 1 leverage	$ 69,213	$ 69,938
Ratio
Common Equity Tier 1 capital	15.50%	16.50%
Tier 1 capital	17.70%	18.90%
Total capital	20.30%	21.70%
Tier 1 leverage	8.20%	8.30%
SLR	6.30%
Required Ratio
SLR	5.00%
MSBNA
Amount
Common Equity Tier 1 capital	$ 15,514	$ 15,196
Tier 1 capital	15,514	15,196
Total capital	15,785	15,454
Tier 1 leverage	$ 15,514	$ 15,196
Ratio
Common Equity Tier 1 capital	19.70%	20.50%
Tier 1 capital	19.70%	20.50%
Total capital	20.10%	20.80%
Tier 1 leverage	11.80%	11.80%
SLR	9.00%
Required Ratio
Common Equity Tier 1 capital	6.50%	6.50%
Tier 1 capital ratio	8.00%	8.00%
Total capital ratio	10.00%	10.00%
Tier 1 leverage ratio	5.00%	5.00%
SLR	6.00%
MSPBNA
Amount
Common Equity Tier 1 capital	$ 6,382	$ 6,215
Tier 1 capital	6,382	6,215
Total capital	6,425	6,258
Tier 1 leverage	$ 6,382	$ 6,215
Ratio
Common Equity Tier 1 capital	24.20%	24.40%
Tier 1 capital	24.20%	24.40%
Total capital	24.40%	24.60%
Tier 1 leverage	9.70%	9.70%
SLR	9.30%
Required Ratio
Common Equity Tier 1 capital	6.50%	6.50%
Tier 1 capital ratio	8.00%	8.00%
Total capital ratio	10.00%	10.00%
Tier 1 leverage ratio	5.00%	5.00%
SLR	6.00%

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The minimum percentage of tier one capital to total leverage exposure, as defined by regulatory framework.

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Tier 1 risk-based capital divided by adjusted average assets as defined in the regulations.

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Tier 1 Risk Based Common Capital as defined in the regulations.

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The common equity Tier 1 capital ratio (Tier 1 common equity capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

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Tier 1 common capital divided by risk weighted assets as defined by regulations.

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The amount of total capital as defined in the regulations.

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The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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Total Capital divided by risk weighted assets as defined in the regulations.

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Percentage of tier one capital to total leverage exposure, as defined by regulatory framework.

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Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action.

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Tier 1 Risk Based Capital as defined in the regulations.

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Tier 1 capital divided by risk weighted assets as defined by regulations.

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