XML 72 R59.htm IDEA: XBRL DOCUMENT
v3.22.1

Derivatives - Notional Amounts of Foreign Currency Forward Contracts (Parenthetical) (Details) - Other Currencies - USD ($) $ in Millions | Mar. 31, 2022 | Dec. 31, 2021
--- | --- | ---
Designated as hedges |  |
Derivative [Line Items] |  |
Maximum individual currency exposure within various other currencies | $ 25 | $ 25
Not designated as hedges |  |
Derivative [Line Items] |  |
Maximum individual currency exposure within various other currencies | $ 25 | $ 25

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount which no individual currency exposure exceeds within the "Other" notional category for contracts not designated as hedges. + References No definition available. + Details
Name: | wu_MaximumIndividualCurrencyExposureWithinOther
Namespace Prefix: | wu_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | srt_CurrencyAxis=wu_OtherCurrencyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |