Supplemental Financial Data - Other Intangibles (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Finite-lived Intangible Assets [Roll Forward]
Amortization	$ (417.7)	$ (449.7)
Balance at end of period	3,302.2
Indefinite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	1,280.0	1,280.0
Additions at cost	0.0	0.0
Other	0.0	0.0
Balance at end of period	1,280.0	1,280.0
Total
Balance at beginning of period	4,320.1	4,824.5
Additions at cost	0.7	0.7
Amortization	(417.7)	(449.7)
Other	12.8	(55.4)
Balance at end of period	3,915.9	4,320.1
Noncash or part noncash acquisition, intangible assets acquired	7.9	15.0
Accounts Payable and Other Accrued Liabilities, Current
Total
Noncash or part noncash acquisition, intangible assets acquired	4.6	10.3
Other Noncurrent Liabilities
Total
Noncash or part noncash acquisition, intangible assets acquired	2.6	4.7
Customer relationships
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	1,536.7	1,793.3
Additions at cost	0.0	0.0
Amortization	(221.9)	(240.3)
Other	1.9	(16.3)
Balance at end of period	1,316.7	1,536.7
Total
Amortization	(221.9)	(240.3)
Accumulated amortization of intangibles	1,212.7	988.9
Reacquired rights
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	245.5	284.7
Additions at cost	0.0	0.0
Amortization	(18.9)	(18.7)
Other	7.3	(20.5)
Balance at end of period	233.9	245.5
Total
Amortization	(18.9)	(18.7)
Accumulated amortization of intangibles	63.4	42.6
Database
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	1,100.0	1,285.1
Additions at cost	0.0	0.0
Amortization	(160.1)	(173.8)
Other	0.7	(11.3)
Balance at end of period	940.6	1,100.0
Total
Amortization	(160.1)	(173.8)
Accumulated amortization of intangibles	872.8	711.4
Other intangibles
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	157.9	181.4
Additions at cost	0.7	0.7
Amortization	(16.8)	(16.9)
Other	2.9	(7.3)
Balance at end of period	144.7	157.9
Total
Amortization	(16.8)	(16.9)
Accumulated amortization of intangibles	$ 77.1	$ 59.1