Segments - Reportable Segments Results (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		11 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020
Revenues:
Total consolidated revenues	$ 1,114.7	$ 1,340.5	$ 2,304.7	$ 2,677.5
Operating income:
Total operating income	221.8	258.9	455.0	510.1
Restructuring-related expenses and business transformation expenses	(5.2)	(7.4)	(15.7)	(7.4)	$ (131.2)
Consumer-to-Consumer | Change in Accounting Method
Operating income:
Total operating income		(11.7)		(24.8)
Other | Change in Accounting Method
Operating income:
Total operating income		11.7		24.8
Operating Segments
Operating income:
Total operating income	227.0	266.3	470.7	517.5
Operating Segments | Consumer-to-Consumer
Revenues:
Total consolidated revenues	976.6	1,112.9	1,992.0	2,169.8
Operating income:
Total operating income	212.8	250.2	422.7	483.5
Operating Segments | Business Solutions
Revenues:
Total consolidated revenues	79.4	95.6	177.8	191.2
Operating income:
Total operating income	1.3	10.5	15.2	19.1
Operating Segments | Other
Revenues:
Total consolidated revenues	58.7	132.0	134.9	316.5
Operating income:
Total operating income	$ 12.9	5.6	$ 32.8	14.9
Operating Segments | Other | Speedpay | Divestitures
Revenues:
Revenues		37.2		125.4
Operating income:
Operating expenses		30.6		98.2
Operating Segments | Other | Paymap | Divestitures
Revenues:
Revenues		1.6		5.3
Operating income:
Operating expenses		$ 0.5		$ 2.2