Reportable Business Segments and International Operations, Reconciliation of Segment Operating Income to Consolidated Income Before Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information
Operating income	$ 488.4	$ 475.8	$ 357.4	$ 316.9	$ 429.8	$ 413.6	$ 399.5	$ 376.2	$ 1,638.4	$ 1,619.2	$ 1,686.9
Stock-based compensation expense									(70.5)	(63.0)	(55.6)
Acquisition-related expenses	$ (11.5)						$ (8.9)	$ (16.5)	(11.5)	(25.4)	(8.5)
Other operating expenses									(56.2)	(54.6)	(54.1)
Interest expense									(115.4)	(117.6)	(101.7)
Loss on early extinguishment of debt						$ (14.3)			0.0	(14.3)	0.0
Other income, net									3.6	8.6	3.2
Income before income taxes									1,526.6	1,495.9	1,588.4
Operating Segment
Segment Reporting Information
Operating income									$ 1,776.6	$ 1,762.2	$ 1,805.1