Goodwill and Intangible Assets - Other Intangibles (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022
Finite-lived Intangible Assets [Roll Forward]
Amortization	$ (103.9)	$ (106.7)	$ (112.0)	$ (115.8)
Other indefinite-lived intangibles
Balance at beginning of period	1,280.0	1,280.0	1,280.0	1,280.0
Additions at cost	0.0	0.0	0.0	0.0
Other	0.0	0.0	0.0	0.0
Balance at end of period	1,280.0	1,280.0	1,280.0	1,280.0
Total
Balance at beginning of period	4,218.6	4,320.1	4,689.7	4,824.5
Additions at cost	0.1	0.1	0.2	0.2
Amortization	(103.9)	(106.7)	(112.0)	(115.8)
Other	(1.5)	5.1	(36.2)	(19.2)
Balance at end of period	4,113.3	4,218.6	4,541.7	4,689.7
Customer relationships
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	1,481.0	1,536.7	1,726.7	1,793.3
Additions at cost	0.0	0.0	0.0	0.0
Amortization	(55.1)	(56.8)	(59.7)	(61.9)
Other	(1.5)	1.1	(9.6)	(4.7)
Balance at end of period	1,424.4	1,481.0	1,657.4	1,726.7
Total
Amortization	(55.1)	(56.8)	(59.7)	(61.9)
Reacquired rights
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	243.6	245.5	271.7	284.7
Additions at cost	0.0	0.0	0.0	0.0
Amortization	(4.8)	(4.7)	(4.7)	(5.1)
Other	0.0	2.8	(15.7)	(7.9)
Balance at end of period	238.8	243.6	251.3	271.7
Total
Amortization	(4.8)	(4.7)	(4.7)	(5.1)
Database
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	1,059.1	1,100.0	1,235.9	1,285.1
Additions at cost	0.0	0.0	0.0	0.0
Amortization	(39.8)	(41.0)	(43.2)	(44.6)
Other	(1.7)	0.1	(5.9)	(4.6)
Balance at end of period	1,017.6	1,059.1	1,186.8	1,235.9
Total
Amortization	(39.8)	(41.0)	(43.2)	(44.6)
Other intangibles
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	154.9	157.9	175.4	181.4
Additions at cost	0.1	0.1	0.2	0.2
Amortization	(4.2)	(4.2)	(4.4)	(4.2)
Other	1.7	1.1	(5.0)	(2.0)
Balance at end of period	152.5	154.9	166.2	175.4
Total
Amortization	$ (4.2)	$ (4.2)	$ (4.4)	$ (4.2)