Guarantees and Contingent Liabilities - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Securities Lending Indemnifications [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Maximum Potential Future Payments	$ 4,468
Collateral Held	4,564
Tender Option Bond Program Guarantee [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Maximum Potential Future Payments	2,725
Collateral Held	2,994
Minimum Revenue Guarantees [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Maximum Potential Future Payments	3
Standby Letters of Credit [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Maximum Potential Future Payments	$ 10,258
Weighted-average term of standby letter of credit arrangements	21 months
Carrying Amount	$ 48
Third Party Borrowing Arrangements [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Maximum Potential Future Payments	7
Asset Sales [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Maximum Potential Future Payments	5,069
Carrying Amount	68
Merchant Processing [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Maximum Potential Future Payments	108,875
Carrying Amount	61
Collateral Held	589
Airline Processing Arrangements [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Value of airline tickets purchased to deliver at future date through card transactions	8,300
Representation and Warranty [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Carrying Amount	9	$ 10
Unresolved representation and warranty claims from GSEs	10	$ 15
Tax Advantaged Investments Sales [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Carrying Amount	68
Unresolved Merchant Charge-backs [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Carrying Amount	89
Collateral Held	17
Escrow Deposits Letters of Credit Indemnities [Member] \| Airline Processing Arrangements [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Collateral Held	496
Merchant Escrow Deposits [Member] \| Airline Processing Arrangements [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Collateral Held	44
Wholly Owned Unconsolidated Trust [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Maximum Potential Future Payments	$ 681
Percentage of common equity in wholly owned USB Capital IX	100.00%
Total assets of trust consisting primarily of Series A Preferred Stock	$ 682
Subsidiaries Financial Performance [Member]
Guarantees And Contingent Liabilities (Textual) [Abstract]
Maximum Potential Future Payments	$ 781

The total amount of cash and securities held by third party trustees pursuant to terms of debt instruments or other agreements as of the date of each statement of financial position presented, which can be used by the trustee only to pay the noncurrent portion of specified obligations.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(b))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_AssetsHeldInTrust
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118943654&loc=d3e12069-110248

+ Details

Name:	us-gaap_GuaranteeObligationsCurrentCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=118943654&loc=d3e12069-110248

+ Details

Name:	us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Describe the approximate term of the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=118943654&loc=d3e12069-110248

+ Details

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

- Definition

Guarantee obligations collateral held.

+ References

No definition available.

+ Details

Name:	usb_GuaranteeObligationsCollateralHeld
Namespace Prefix:	usb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Guarantees and contingent liabilities.

+ References

No definition available.

+ Details

Name:	usb_GuaranteesAndContingentLiabilitiesTextualAbstract
Namespace Prefix:	usb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest in unconsolidated trusts.

+ References

No definition available.

+ Details

Name:	usb_InterestInUnconsolidatedTrusts
Namespace Prefix:	usb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Loss contingency pending claims amount.

+ References

No definition available.

+ Details

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

- Definition

Value of airline tickets purchased to deliver at future date through card transactions.

+ References

No definition available.

+ Details

Name:	usb_ValueOfAirlineTicketsPurchasedToDeliverAtFutureDateThroughCardTransactions
Namespace Prefix:	usb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=us-gaap_IndemnificationGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=usb_TenderOptionBondProgramGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=us-gaap_GuaranteeOfBusinessRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=us-gaap_StandbyLettersOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=usb_ThirdPartyBorrowingArrangementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=usb_AssetsSalesArrangementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=usb_MerchantProcessingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=usb_AirlineProcessingArrangementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=usb_RepresentationAndWarrantyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=usb_TaxAdvantagedInvestmentsSalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=usb_UnresolvedMerchantChargeBacksMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_UnderlyingAssetClassAxis=usb_EscrowDepositsLettersOfCreditIndemnitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_UnderlyingAssetClassAxis=usb_MerchantEscrowDepositsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=usb_WhollyOwnedUnconsolidatedTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=usb_SubsidiariesFinancialPerformanceMember
Namespace Prefix:
Data Type:	na
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Period Type: