Earnings Per Share - Components of Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net income attributable to U.S. Bancorp	$ 1,489	$ 1,471	$ 4,403	$ 4,363
Preferred dividends	(62)	(60)	(182)	(181)
Earnings allocated to participating stock awards	(5)	(6)	(17)	(19)
Net income applicable to U.S. Bancorp common shareholders	$ 1,422	$ 1,405	$ 4,204	$ 4,163
Average common shares outstanding	1,758	1,798	1,770	1,809
Net effect of the exercise and assumed purchase of stock awards	8	9	8	10
Average diluted common shares outstanding	1,766	1,807	1,778	1,819
Earnings per common share	$ 0.81	$ 0.78	$ 2.38	$ 2.30
Diluted earnings per common share	$ 0.81	$ 0.78	$ 2.36	$ 2.29