Accounting Changes - Additional Information (Detail) $ in Billions	Mar. 31, 2019 USD ($)
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Increase in lease assets related to adoption of accounting guidance	$ 1.3
Increase in lease related liabilities related to adoption of accounting guidance	$ 1.3

New accounting pronouncement or change in accounitng principle effect of adoption on lease related liabilities.

No definition available.

Name:	usb_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfAdoptionOnLeaseRelatedLiabilities
Namespace Prefix:	usb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant