Stockholder's Equity (Reclassification out of Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification out of Accumulated Other Comprehensive Income
Revenue	$ 2,960.9	$ 3,845.0	$ 6,086.1	$ 7,233.0
Selling, general and administrative expense	(281.4)	(268.0)	(584.5)	(522.1)
Research and development expense	(53.6)	(49.1)	(94.7)	(92.5)
Other income (expense), net	2.2	(50.3)	(23.0)	13.2
Income before income taxes	174.8	245.2	315.5	281.8
Provision for income taxes (Note 16)	64.7	86.2	114.0	138.0
Net income	110.1	159.0	201.5	143.8
Amount Reclassified out of Accumulated Other Comprehensive Loss
Reclassification out of Accumulated Other Comprehensive Income
Amortization of actuarial gain (loss)		(0.7)		(1.2)
Amortization of prior service credit (cost)	(0.3)	(0.1)	(0.3)	(0.3)
Income before income taxes	(0.3)	(0.8)	(0.3)	(1.5)
Provision for income taxes (Note 16)		(0.2)		(0.4)
Net income	(0.3)	(0.6)	(0.3)	(1.1)
Amount Reclassified out of Accumulated Other Comprehensive Loss | Hedging | Foreign exchange contracts
Reclassification out of Accumulated Other Comprehensive Income
Provision for income taxes (Note 16)	0.8	(10.4)	0.6	(19.3)
Net income	$ 3.6	$ (20.3)	$ 3.4	$ (54.7)