Reportable Business Segments and International Operations, Reconciliation of Segment Operating Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information
Operating income	$ 429.8	$ 413.6	$ 399.5	$ 376.2	$ 457.6	$ 444.2	$ 408.2	$ 376.9	$ 1,619.2	$ 1,686.9	$ 1,427.6
Interest expense									(117.6)	(101.7)	(92.3)
Loss on early extinguishment of debt		$ (14.3)							(14.3)	0.0	0.0
Other income, net									8.6	3.2	17.1
Stock-based compensation expense									(63.0)	(55.6)	(49.7)
Acquisition-related expenses			$ (8.9)	$ (16.5)	$ (8.5)				(25.4)	(8.5)	(4.0)
Other operating expenses									(54.6)	(54.1)	(48.1)
Income before income taxes									1,495.9	1,588.4	1,352.4
Operating Segment
Segment Reporting Information
Operating income									$ 1,762.2	$ 1,805.1	$ 1,529.4