2.2.0.7 false Commitments and Contingencies (Details) (USD $) 0607 - Disclosure - Commitments and Contingencies (Details) true false In Millions false false 1 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ false 2 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 3 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ 3 Commitments and Contingencies (Numeric) [Abstract] 1 wu_CommitmentsAndContingenciesNumericAbstract wu false na duration Commitments And Contingencies Numeric Abstract false false false false false true false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string Commitments And Contingencies Numeric Abstract false 4 Outstanding letters of credit and bank guarantees 2 wu_OutstandingLettersOfCreditAndBankGuarantees wu false credit instant Outstanding letters of credit and bank guarantees primarily held in connection with lease arrangements and certain agent... false false false false false false false false false false false verboselabel false 1 true true false false 84300000 84.3 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:monetaryItemType monetary Outstanding letters of credit and bank guarantees primarily held in connection with lease arrangements and certain agent agreements. No authoritative reference available. false 5 Accrual for anticipated agreement and settlement 2 us-gaap_LossContingencyAccrualAtCarryingValue us-gaap true credit instant No definition available. false false false false false false false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false true false false 71000000 71.0 false false false 3 false false false false 0 0 false false false xbrli:monetaryItemType monetary The carrying amount as of the balance sheet date of the combined total of loss contingency reserves. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 5 -Paragraph 9, 10, 11, 12 false 6 Settlement aggreement to invest in compliance 2 wu_SettlementAgreementComplianceInvestment wu false debit instant Represents certain investments in compliance programs along the United States and Mexico border and to engage a monitor for... false false false false false false false false false false false verboselabel false 1 false true false false 23000000 23 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:monetaryItemType monetary Represents certain investments in compliance programs along the United States and Mexico border and to engage a monitor for that program, to be incurred over the next two to four years. No authoritative reference available. false 7 Cash payment related to agreement and settlement 2 us-gaap_PaymentsForLegalSettlements us-gaap true credit duration No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 41000000 41 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:monetaryItemType monetary The amount of cash paid for the settlement of litigation or for other legal issues during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 27 false 8 Recovery of damages for patent infringement 2 us-gaap_GainContingencyUnrecordedAmount us-gaap true credit instant No definition available. false false false false false false false false false false false verboselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 true true false false 16500000 16.5 false false false xbrli:monetaryItemType monetary The amount or range of possible amounts of gain that could be realized upon the resolution of a contingency. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 5 -Paragraph 17 false 3 6 false HundredThousands UnKnown UnKnown false true