Summary of Significant Accounting Policies - Narrative (Details) - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Outstanding restricted stock and options to purchase shares of stock excluded from the diluted earnings per share calculation	15.3	11.6	9.7
Depreciation	$ 35,200,000	$ 37,400,000	$ 39,100,000
Goodwill impairment charge	0	0	0
Amortization expense	$ 130,200,000	$ 141,700,000	$ 144,500,000
Percentage of advertising costs on revenues	3.00%	4.00%	4.00%
ASU 2023-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in accounting principle due to adopted accounting standards update	true
Change in accounting principle, accounting standards update, immaterial effect	true
Change in accounting principle, accounting standards update, adoption date	Dec. 01, 2025
ASU 2023-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in accounting principle due to adopted accounting standards update	true
Change in accounting principle, accounting standards update, immaterial effect	true
Change in accounting principle, accounting standards update, adoption date	Dec. 01, 2024
Other Intangibles
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated future aggregate amortization expense, 2026	$ 153,300,000
Estimated future aggregate amortization expense, 2027	84,600,000
Estimated future aggregate amortization expense, 2028	32,100,000
Estimated future aggregate amortization expense, 2029	15,800,000
Estimated future aggregate amortization expense, 2030	13,200,000
Estimated future aggregate amortization expense, thereafter	$ 21,100,000
Impairments of intangible assets			$ 9,000,000
Impairment, Intangible Asset, Finite-Lived, Statement of Income or Comprehensive Income [Extensible Enumeration]			Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal
Minimum \| Internal Use Software
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amortization period of intangible assets	3 years
Minimum \| Capitalized Contract Costs
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amortization period of intangible assets	5 years
Minimum \| Equipment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property and equipment useful life	3 years
Minimum \| Furniture and Fixtures
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property and equipment useful life	3 years
Maximum \| Uncollected Settlement Assets and Obligations
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Derivative contracts maturity range	1 month
Maximum \| Foreign Currency Denominated Cash and Other Asset and Other Liability Positions
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Derivative contracts maturity range	1 year
Maximum \| Internal Use Software
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amortization period of intangible assets	7 years
Maximum \| Capitalized Contract Costs
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amortization period of intangible assets	10 years
Maximum \| Equipment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property and equipment useful life	7 years
Maximum \| Furniture and Fixtures
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property and equipment useful life	7 years

Western Union CO 10-K