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, 2020		Sep. 30, 2019		Sep. 30, 2020		Sep. 30, 2019
Earnings Per Share [Abstract]
Net income attributable to U.S. Bancorp	$ 1,580		$ 1,908		$ 3,440		$ 5,428
Preferred dividends	(79)	[1]	(79)	[1]	(229)	[2]	(230)	[3]
Earnings allocated to participating stock awards	(7)		(8)		(15)		(23)
Net income applicable to U.S. Bancorp common shareholders	$ 1,494		$ 1,821		$ 3,196		$ 5,175
Average common shares outstanding	1,506		1,575		1,510		1,589
Net effect of the exercise and assumed purchase of stock awards	1		3		1		3
Average diluted common shares outstanding	1,507		1,578		1,511		1,592
Earnings per common share	$ 0.99		$ 1.16		$ 2.12		$ 3.26
Diluted earnings per common share	$ 0.99		$ 1.15		$ 2.11		$ 3.25

[1] Reflects dividends declared per share on the Company’s Series A, Series B, Series F, Series H, Series J and Series K Non-Cumulative Perpetual Preferred Stock of $894.444, $223.61, $406.25, $321.88, $662.50 and $343.75, respectively.

[2] Reflects dividends declared per share on the Company’s Series A, Series B, Series F, Series H, Series I, Series J and Series K Non-Cumulative Perpetual Preferred Stock of $2,663.888, $665.97, $1,218.75, $965.64, $640.625, $1,325.00 and $1,031.25, respectively.

[3] Reflects dividends declared per share on the Company’s Series A, Series B, Series F, Series H, Series I, Series J and Series K Non-Cumulative Perpetual Preferred Stock of $2,760.506, $663.54, $1,218.75, $965.64, $640.625, $1,325.00 and $1,031.25, respectively.