Other Comprehensive Income - Changes in Components 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
Equity [Abstract]
Pension and OPEB liability adjustments, Pre-tax	$ 1.1	$ 1.3	$ 2.2	$ 2.6
Unrealized (loss) gain on derivative instruments, Pre-tax	(4.4)	(6.7)	(2.6)	(5.0)
Unrealized foreign currency translation adjustments, Pre-tax	(30.0)	19.8	(20.5)	25.7
Total other comprehensive income (loss), Pre-tax	(33.3)	14.4	(20.9)	23.3
Pension and OPEB liability adjustments, Tax	(0.3)	(0.2)	(0.7)	(0.4)
Unrealized (loss) gain on derivative instruments, Tax	1.4	2.4	1.3	2.0
Unrealized foreign currency translation adjustments, Tax	(0.8)	0.0	(1.9)	0.0
Total other comprehensive income (loss), Tax	0.3	2.2	(1.3)	1.6
Pension and OPEB liability adjustments, Net of Tax	0.8	1.1	1.5	2.2
Unrealized gain (loss) on financial instruments, net of realized gain (loss), Net of Tax	(3.0)	(4.3)	(1.3)	(3.0)
Unrealized foreign currency translation adjustments, Net of Tax	(30.8)	19.8	(22.4)	25.7
Other comprehensive (loss) income	$ (33.0)	$ 16.6	$ (22.2)	$ 24.9

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Amount before tax, after reclassification adjustments of other comprehensive income (loss).

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Amount before tax, after reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount before tax, after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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