Stockholders' Equity (Reclassification Out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue		$ 3,683.0	$ 4,140.9	$ 3,845.0	$ 3,388.0	$ 2,047.7	$ 2,375.7	$ 2,370.5	$ 2,405.7	$ 15,056.9		$ 9,199.6	$ 11,471.9
Selling, general and administrative expense										(1,060.9)		(572.6)	(689.6)
Other income (expense), net										(25.9)		6.5	(102.9)
Income before income taxes	[1]									679.7		551.4	150.5
Provision (benefit) for income taxes										545.5		180.3	136.5
Net income		$ (127.5)	$ 117.9	$ 159.0	$ (15.2)	$ (155.0)	$ 301.7	$ 103.8	$ 120.6	134.2		371.1	14.0
Defined pension and other post-retirement benefits | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes										21.8		9.0	(4.4)
Provision (benefit) for income taxes										9.1		2.8	(1.3)
Net income										12.7		6.2	(3.1)
Settlements and curtailments										25.3	[2]	10.7	0.0
Foreign exchange contract | Hedging | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue										(39.3)		0.0	0.0
Costs of sales										5.3		0.0	0.0
Selling, general and administrative expense										0.8		0.0	0.0
Other income (expense), net										(102.2)		(165.7)	(93.6)
Income before income taxes										(135.4)		(165.7)	(93.6)
Provision (benefit) for income taxes										(34.2)		(45.6)	(25.8)
Net income										(101.2)		(120.1)	(67.8)
International | Pensions
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Settlements and curtailments										1.5		(10.7)	0.0
Amortization of actuarial gain (loss)										(2.5)		(1.0)	(3.7)
Amortization of prior service credit (cost)										$ (1.0)		$ (0.7)	$ (0.7)

[1] Includes amounts attributable to noncontrolling interests.

[2] These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 18 for additional details).