Earnings Per Share - Components of Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Net income attributable to U.S. Bancorp	$ 1,483	$ 1,495	$ 2,914	$ 2,892
Preferred dividends	(60)	(61)	(120)	(121)
Earnings allocated to participating stock awards	(6)	(7)	(12)	(13)
Net income applicable to U.S. Bancorp common shareholders	$ 1,417	$ 1,427	$ 2,782	$ 2,758
Average common shares outstanding	1,771	1,811	1,776	1,815
Net effect of the exercise and assumed purchase of stock awards	8	10	8	10
Average diluted common shares outstanding	1,779	1,821	1,784	1,825
Earnings per common share	$ 0.80	$ 0.79	$ 1.57	$ 1.52
Diluted earnings per common share	$ 0.80	$ 0.78	$ 1.56	$ 1.51