Reportable Business Segments, Reconciliation of Segment Operating Income to Consolidated Income Before Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information
Operating income	$ 413.6	$ 444.2	$ 1,189.4	$ 1,229.3
Interest expense	(29.7)	(24.8)	(89.5)	(75.3)
Loss on early extinguishment of debt	(14.3)	0.0	(14.3)	0.0
Other income, net	4.5	0.2	7.6	2.5
Stock-based compensation expense	(16.6)	(14.4)	(46.4)	(40.4)
Acquisition-related expenses	0.0	0.0	(25.4)	0.0
Other operating expenses	(13.9)	(13.9)	(40.5)	(39.6)
Income before income taxes	374.1	419.6	1,093.2	1,156.5
Operating Segment
Segment Reporting Information
Operating income	$ 444.1	$ 472.5	$ 1,301.7	$ 1,309.3