Stockholders' Equity (Reclassification Out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues		$ 3,323.0	$ 3,143.8	$ 2,960.9	$ 3,125.2	$ 3,683.0	$ 4,140.9	$ 3,845.0	$ 3,388.0	$ 12,552.9	$ 15,056.9	$ 9,199.6
Selling, general and administrative expense										(1,140.6)	(1,060.9)	(572.6)
Other income (expense), net										(323.9)	(25.9)	6.5
Income (loss) before income taxes	[1]									(1,488.1)	679.7	551.4
Provision (benefit) for income taxes										422.7	545.5	180.3
Net income (loss)		$ (2,246.5)	$ 134.2	$ 110.1	$ 91.4	$ (127.5)	$ 117.9	$ 159.0	$ (15.2)	(1,910.8)	134.2	371.1
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Provision (benefit) for income taxes										0.1	9.1
Accumulated Foreign Currency Adjustment Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net										41.1
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 (loss) before income taxes										1.1	21.8	9.0
Provision (benefit) for income taxes												2.8
Net income (loss)										1.0	12.7	6.2
Settlements and curtailments	[2]									3.0	25.3	10.7
Foreign exchange contract | Hedging | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Provision (benefit) for income taxes										(0.1)	(34.2)	(45.6)
Net income (loss)										2.0	(101.2)	(120.1)
International | Pensions
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Settlements and curtailments										(3.4)	1.5	(10.7)
Amortization of actuarial gain (loss)	[2]									0.6	2.5	1.0
Amortization of prior service credit (cost)	[2]									(1.3)	(1.0)	(0.7)
Cash flow hedging | Foreign exchange contract | Hedging | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues										(2.4)	(39.3)
Costs of sales										3.4	5.3
Selling, general and administrative expense										(0.1)	0.8
Other income (expense), net										1.0	(102.2)	(165.7)
Income (loss) before income taxes										$ 1.9	$ (135.4)	$ (165.7)

[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 20 for additional details).