Reportable Business Segments and International Operations, Reconciliation of Segment Operating Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income	$ 339.1	$ 326.3	$ 300.3	$ 239.4	$ 289.0	$ 294.8	$ 260.7	$ 260.2	$ 1,205.2	$ 1,104.7	$ 1,034.6
Interest expense									(72.6)	(68.3)	(80.4)
Other income, net									8.5	16.4	18.3
Stock-based compensation expense									(47.6)	(44.2)	(41.4)
Acquisition-related expenses									(36.6)	(5.7)	(14.1)
Other operating expenses									(43.7)	(44.0)	(41.6)
Income before income taxes									1,141.1	1,052.8	972.5
Operating Segment
Reconciliation of segment operating income to consolidated income before income taxes
Segment operating income									$ 1,333.1	$ 1,198.6	$ 1,131.7