Accounting Changes - Additional Information (Detail) - Accounting Standards Update 2016-13 [Member] - USD ($) $ in Millions		3 Months Ended
Jan. 01, 2020	Mar. 31, 2020
Increase in allowance for credit losses due to new accounting standard	$ 1,500
Decrease in retained earnings due to new accounting standard	$ 1,100
Increase in the allowance for credit losses due to deteriorating economic conditions		$ 600

Financing receivable allowance for credit losses increase due to new accounting standard.

No definition available.

Name:	usb_FinancingReceivableAllowanceForCreditLossesIncreaseDueToNewAccountingStandard
Namespace Prefix:	usb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration