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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net income attributable to U.S. Bancorp	$ 1,750	$ 1,500	$ 3,425	$ 2,973
Preferred dividends	(64)	(64)	(134)	(133)
Impact of preferred stock redemption				(10)
Earnings allocated to participating stock awards	(8)	(6)	(16)	(13)
Net income applicable to U.S. Bancorp common shareholders	$ 1,678	$ 1,430	$ 3,275	$ 2,817
Average common shares outstanding	1,642	1,684	1,647	1,689
Net effect of the exercise and assumed purchase of stock awards	4	6	4	6
Average diluted common shares outstanding	1,646	1,690	1,651	1,695
Earnings per common share	$ 1.02	$ 0.85	$ 1.99	$ 1.67
Diluted earnings per common share	$ 1.02	$ 0.85	$ 1.98	$ 1.66