Stockholder's Equity (Reclassification out of Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reclassification out of Accumulated Other Comprehensive Income
Revenue	$ 3,143.8	$ 4,140.9	$ 9,229.9	$ 11,373.9
Selling, general and administrative expense	(250.6)	(284.4)	(835.1)	(806.5)
Research and development expense	(38.6)	(51.1)	(133.3)	(143.6)
Other income (expense), net	(10.4)	(30.0)	12.6	(43.2)
Income before income taxes	200.9	229.6	516.4	511.4
Provision for income taxes (Note 16)	66.7	111.7	180.7	249.7
Net income	134.2	117.9	335.7	261.7
Amount Reclassified out of Accumulated Other Comprehensive Loss
Reclassification out of Accumulated Other Comprehensive Income
Amortization of actuarial gain (loss)		(0.7)		(1.9)
Amortization of prior service credit (cost)	(0.3)	(0.3)	(0.6)	(0.6)
Income before income taxes	(0.3)	(1.0)	(0.6)	(2.5)
Provision for income taxes (Note 16)		(0.3)		(0.7)
Net income	(0.3)	(0.7)	(0.6)	(1.8)
Amount Reclassified out of Accumulated Other Comprehensive Loss | Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Reclassification out of Accumulated Other Comprehensive Income
Other income (expense), net	(41.1)		(41.1)
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)	1.2	(6.3)	1.8	(25.6)
Net income	$ 3.8	$ (19.7)	$ 7.2	$ (74.3)