Segments - Reportable Segments Results (Details) - USD ($) $ in Millions	3 Months Ended		15 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020
Revenues:
Total consolidated revenues	$ 1,190.0	$ 1,337.0
Operating income:
Total operating income	233.2	251.2
Restructuring-related expenses and business transformation expenses	(10.5)		$ (126.0)
Consumer-to-Consumer | Change in Accounting Method
Operating income:
Total operating income		(13.1)
Other | Change in Accounting Method
Operating income:
Total operating income		13.1
Operating Segments
Operating income:
Total operating income	243.7	251.2
Operating Segments | Consumer-to-Consumer
Revenues:
Total consolidated revenues	1,015.4	1,056.9
Operating income:
Total operating income	209.9	233.3
Operating Segments | Business Solutions
Revenues:
Total consolidated revenues	98.4	95.6
Operating income:
Total operating income	13.9	8.6
Operating Segments | Other
Revenues:
Total consolidated revenues	76.2	184.5
Operating income:
Total operating income	$ 19.9	9.3
Operating Segments | Other | Speedpay | Divestitures
Revenues:
Revenues		88.2
Operating income:
Operating expenses		67.6
Operating Segments | Other | Paymap | Divestitures
Revenues:
Revenues		3.7
Operating income:
Operating expenses		$ 1.7