Investment Securities - Amount of Gross Gains and Losses Realized through Sales of Available for Sale Investment Securities (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Investments Debt And Equity Securities [Abstract]
Realized gains		$ 115	$ 21	$ 145
Realized losses		(99)		(99)
Net realized gains (losses)		16	21	46
Income tax (benefit) on net realized gains (losses)		$ 7	$ 8	$ 18

Available For Sale Securities Gross Realized Gain Loss Excluding Other Than Temporary Impairments Income Tax Expense Benefit

No definition available.

+ Details

Name:	usb_AvailableForSaleSecuritiesGrossRealizedGainLossExcludingOtherThanTemporaryImpairmentsIncomeTaxExpenseBenefit
Namespace Prefix:	usb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26805-111562

+ Details

Name:	us-gaap_AvailableforsaleSecuritiesGrossRealizedGainLossExcludingOtherThanTemporaryImpairments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesGrossRealizedGains
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities and excluding other than temporary impairments (OTTI), if any, recognized elsewhere.

+ References

No definition available.

+ Details

Name:	us-gaap_AvailableforsaleSecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration