Segments - Segments Results (Parenthetical) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating income:
Total operating income	$ 1,123.1	$ 967.3	$ 934.0
Consumer-to-Consumer | Change in Accounting Method
Operating income:
Total operating income			(49.6)
Other | Change in Accounting Method
Operating income:
Total operating income			49.6
Operating Segments
Operating income:
Total operating income	1,123.1	1,004.1	1,049.5
Operating Segments | Consumer-to-Consumer
Operating income:
Total operating income	977.6	924.7	975.4
Operating Segments | Other
Operating income:
Total operating income	$ 50.0	$ 55.0	27.3
Operating Segments | Other | Speedpay | Divestitures
Revenues:
Revenues			125.4
Operating income:
Operating expenses			98.2
Operating Segments | Other | Paymap | Divestitures
Revenues:
Revenues			5.3
Operating income:
Operating expenses			$ 2.2