Supplemental Financial Data - Other Intangibles (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Feb. 07, 2019	Jun. 30, 2021	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Finite-lived Intangible Assets [Roll Forward]
Amortization			$ (490.7)		$ (456.9)
WWN Relationship Transfer		$ 0.0
Balance at end of period			4,102.0
Indefinite-lived Intangible Assets [Roll Forward]
Balance at beginning of period			1,275.8		1,275.8
Acquisitions			0.0
Additions at cost			4.2		0.0
Other			0.0		0.0
Balance at end of period			1,280.0		1,275.8		$ 1,275.8
Total
Balance at beginning of period			4,814.8	[1]	5,254.5
Acquisitions			532.4		9.2
Additions at cost			11.8		0.8
Amortization			(490.7)		(456.9)
Other			(43.8)		7.2
Balance at end of period			4,824.5		4,814.8	[1]	5,254.5
In-place lease intangibles			7.1
Noncash or part noncash acquisition, intangible assets acquired			7.9
Accounts Payable and Accrued Liabilities
Total
Noncash or part noncash acquisition, intangible assets acquired			0.9
Other Noncurrent Liabilities
Total
Noncash or part noncash acquisition, intangible assets acquired			2.5
Deferred Income Tax
Total
Noncash or part noncash acquisition, intangible assets acquired			4.5
Customer relationships
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period			1,912.9		2,162.7
Acquisitions			147.8		2.4
Additions at cost			0.0		0.0
Amortization			(259.0)		(255.2)
Other			(8.4)		3.0
Balance at end of period			1,793.3		1,912.9		2,162.7
Total
Amortization			(259.0)		(255.2)
Accumulated amortization of intangibles			755.1		497.0
Reacquired rights
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period			0.0		0.0
Acquisitions			270.0		0.0
Additions at cost			0.0		0.0
Amortization			(26.6)		0.0
WWN Relationship Transfer		64.7
Other			(23.4)		0.0
Balance at end of period			284.7		0.0		0.0
Total
Amortization			(26.6)		0.0
Database
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period			1,369.4		1,550.6
Acquisitions			113.2		0.0
Additions at cost			0.0		0.1
Amortization			(188.6)		(181.3)
Other			(8.9)		0.0
Balance at end of period			1,285.1		1,369.4		1,550.6
Total
Amortization			(188.6)		(181.3)
Accumulated amortization of intangibles			540.4		352.7
Other intangibles
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period			256.7		265.4
Acquisitions			1.4		6.8
Additions at cost			7.6		0.7
Amortization	$ (3.2)		(16.5)		(20.4)		(428.1)
WWN Relationship Transfer		$ (64.7)
Other			(3.1)		4.2
Balance at end of period			181.4		256.7		265.4
Total
Amortization	$ (3.2)		(16.5)		(20.4)		$ (428.1)
Accumulated amortization of intangibles			$ 44.2		$ 37.8

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