Goodwill and Other Intangibles - Other Intangibles (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021		Mar. 31, 2020
Finite-lived Intangible Assets [Roll Forward]
Amortization	$ (122.4)		$ (116.1)
Relationship Transfer	0.0
Indefinite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	1,275.8		1,275.8
Acquisition	0.0		0.0
Additions at cost	0.0		0.0
Other	0.0		0.0
Balance at end of period	1,275.8		1,275.8
Total
Balance at beginning of period	4,814.8	[1]	5,254.5
Acquisition	493.0		9.2
Additions at cost	0.2		0.2
Amortization	(122.4)		(116.1)
Other	(27.9)		(13.4)
Balance at end of period	5,157.7		5,134.4
Customer Relationships
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	1,912.9		2,162.7
Acquisition	106.0		2.4
Additions at cost	0.0		0.0
Amortization	(65.6)		(64.9)
Other	(5.4)		(3.9)
Balance at end of period	1,947.9		2,096.3
Total
Amortization	(65.6)		(64.9)
Reacquired Rights
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	0.0		0.0
Acquisition	271.0		0.0
Additions at cost	0.0		0.0
Amortization	(5.0)		0.0
Relationship Transfer	64.7
Other	(14.3)		0.0
Balance at end of period	316.4		0.0
Total
Amortization	(5.0)		0.0
Database
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	1,369.7		1,550.8
Acquisition	116.0		0.0
Additions at cost	0.0		0.0
Amortization	(47.8)		(46.2)
Other	(6.2)		0.0
Balance at end of period	1,431.7		1,504.6
Total
Amortization	(47.8)		(46.2)
Other Intangibles
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	256.4		265.2
Acquisition	0.0		6.8
Additions at cost	0.2		0.2
Amortization	(4.0)		(5.0)
Relationship Transfer	(64.7)
Other	(2.0)		(9.5)
Balance at end of period	185.9		257.7
Total
Amortization	$ (4.0)		$ (5.0)

[1] See discussion in Note 1 - Basis of Presentation for further detail regarding the elimination of the International lag reporting.