Earnings Per Share - Components of Earnings per Share (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Earnings Per Share [Abstract]
Net income attributable to U.S. Bancorp	$ 1,428	$ 1,338
Preferred dividends	(64)	(46)
Earnings allocated to participating stock awards	(6)	(7)
Net income applicable to U.S. Bancorp common shareholders	$ 1,358	$ 1,285
Average common shares outstanding	1,858	1,901
Net effect of the exercise and assumed purchase of stock awards	9	9
Average diluted common shares outstanding	1,867	1,910
Earnings per common share	$ 0.73	$ 0.68
Diluted earnings per common share	$ 0.73	$ 0.67

Equity impact of aggregate cash, stock, and paid-in-kind dividends declared for preferred shareholders during the period.

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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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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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