Earnings Per Share - Components of Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net income attributable to U.S. Bancorp	$ 6,218	$ 5,888	$ 5,879
Preferred dividends	(267)	(281)	(247)
Impact of preferred stock redemption	(10)
Impact of the purchase of noncontrolling interests		9
Earnings allocated to participating stock awards	(28)	(27)	(24)
Net income applicable to U.S. Bancorp common shareholders	$ 5,913	$ 5,589	$ 5,608
Average common shares outstanding	1,677	1,718	1,764
Net effect of the exercise and assumed purchase of stock awards	6	6	8
Average diluted common shares outstanding	1,683	1,724	1,772
Earnings per common share	$ 3.53	$ 3.25	$ 3.18
Diluted earnings per common share	$ 3.51	$ 3.24	$ 3.16

Amount of paid and unpaid preferred stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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Amount of undistributed earnings (loss) allocated to participating securities for the basic earnings (loss) per share or per unit calculation under the two-class method.

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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Gain on purchase of noncontrolling interest.

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The stock issuance costs recorded in preferred stock upon the issuance of the Series G Preferred Stock.

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