Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Components of earnings per share
Net income attributable to U.S. Bancorp	$ 1,415	$ 1,203	$ 2,753	$ 2,249
Preferred stock dividends	(64)	(30)	(110)	(69)
Net income applicable to U.S. Bancorp common shareholders	1,345	1,167	2,630	2,170
Average common shares outstanding	1,888	1,921	1,895	1,920
Net effect of the exercise and assumed purchase of stock awards and conversion of outstanding convertible notes	10	8	9	9
Average diluted common shares outstanding	1,898	1,929	1,904	1,929
Earnings allocated to participating stock awards	$ (6)	$ (6)	$ (13)	$ (10)
Earnings per common share	$ 0.71	$ 0.61	$ 1.39	$ 1.13
Diluted earnings per common share	$ 0.71	$ 0.60	$ 1.38	$ 1.12
Stock Option [Member]
Earnings per Share (Textual) [Abstract]
Options outstanding of common shares	23	55	32	55