Reportable Business Segments, Reconciliation of Segment Operating Income to Consolidated Income Before Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information
Operating income	$ 399.5	$ 408.2	$ 775.7	$ 785.1
Interest expense	(30.0)	(26.0)	(59.7)	(50.5)
Other income, net	0.1	0.1	3.1	2.4
Stock-based compensation expense	(15.4)	(13.3)	(29.8)	(26.0)
Acquisition-related expenses	(8.9)	0.0	(25.4)	0.0
Other operating expenses	(13.3)	(12.9)	(26.7)	(25.8)
Income before income taxes	369.6	382.3	719.1	737.0
Operating Segment
Segment Reporting Information
Operating income	$ 437.1	$ 434.4	$ 857.6	$ 836.9