Schedule I - Condensed Financial Information of the Registrant - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Apr. 30, 2021	Dec. 31, 2022		Dec. 31, 2021	Sep. 01, 2022	[2]	Jul. 01, 2022	[2]	Aug. 04, 2021	Mar. 01, 2021	[2]	Jan. 01, 2021	[2]	Dec. 01, 2020	[2]	Nov. 08, 2015
NOTES TO CONDENSED FINANCIAL STATEMENTS
Net assets subject to limitations		$ 710.0
Other liabilities		384.6		$ 269.4
Proceeds from the sale of noncontrolling interest in a private company				50.9
Gain on sale of noncontrolling interest in private company				47.9
Letters of credit outstanding and bank guarantees		390.0
ROU asset		$ 122.4		$ 164.5
Balance sheet location of ROU asset		Other assets		Other assets
Lease liability		$ 161.3		$ 203.0
Balance sheet location of lease liability		Other liabilities		Other liabilities
Lessee, Operating Lease, Existence of Option to Extend [true false]		true
Liability		$ 182.5		$ 821.9
Private Company
NOTES TO CONDENSED FINANCIAL STATEMENTS
Proceeds from the sale of noncontrolling interest in a private company	$ 50.9
Gain on sale of noncontrolling interest in private company				47.9
Minimum
NOTES TO CONDENSED FINANCIAL STATEMENTS
Lease terms		1 year
Maximum
NOTES TO CONDENSED FINANCIAL STATEMENTS
Lease terms		9 years
Lease extension terms		10 years
Reportable Legal Entities | Parent Company
NOTES TO CONDENSED FINANCIAL STATEMENTS
Net assets subject to limitations		$ 710.0
Stated interest rate (as a percent)		2.40%	[1]		2.88%		2.21%			0.12%		0.14%		0.15%
Other liabilities		$ 187.2		93.8
Proceeds from the sale of noncontrolling interest in a private company				50.9
Gain on sale of noncontrolling interest in private company				47.9
Letters of credit outstanding and bank guarantees		370.0
Loss contingency guarantee to an underwriter of a surety bond, payable		200.0
ROU asset		$ 44.1		$ 56.9
Balance sheet location of ROU asset		Other assets		Other assets
Lease liability		$ 80.4		$ 91.3
Balance sheet location of lease liability		Other liabilities		Other liabilities
Lessee, Operating Lease, Existence of Option to Extend [true false]		true		true
Reportable Legal Entities | Parent Company | Revolver - Parent Company
NOTES TO CONDENSED FINANCIAL STATEMENTS
Stated interest rate (as a percent)		0.34%
Maximum borrowing capacity on unsecured borrowing facilities																$ 3,000.0
Outstanding borrowings on unsecured financing facilities		$ 370.0
Reportable Legal Entities | Parent Company | Private Company
NOTES TO CONDENSED FINANCIAL STATEMENTS
Proceeds from the sale of noncontrolling interest in a private company	$ 50.9
Gain on sale of noncontrolling interest in private company				$ 47.9
Reportable Legal Entities | Parent Company | Divestitures | Business Solutions
NOTES TO CONDENSED FINANCIAL STATEMENTS
Consideration from sale of business									$ 910.0
Reportable Legal Entities | Parent Company | Divestitures | Business Solutions | European Union [Member] | Other liabilities
NOTES TO CONDENSED FINANCIAL STATEMENTS
Liability		$ 104.0
Reportable Legal Entities | Parent Company | Minimum
NOTES TO CONDENSED FINANCIAL STATEMENTS
Lease terms		1 year
Reportable Legal Entities | Parent Company | Maximum
NOTES TO CONDENSED FINANCIAL STATEMENTS
Lease terms		9 years
Lease extension terms		10 years

[1] Note is payable to the Parent's 100% owned indirect subsidiary, Western Union International Bank.

[2] This note refinanced a note originally issued on a prior date.