Equity (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Changes in Accumulated Other Comprehensive Income (Loss)
January 1	$ (1,228.5)	$ (963.0)
Cumulative effect of accounting change	(22.3)
Other comprehensive income (loss) before reclassifications	30.7	83.7
Reclassification from accumulated other comprehensive income (loss)	2.1	4.2
March 31	(1,218.0)	(875.1)
Cash Flow Hedge
Changes in Accumulated Other Comprehensive Income (Loss)
January 1	(22.3)	(26.3)
Cumulative effect of accounting change	(5.6)
Other comprehensive income (loss) before reclassifications	0.0	0.0
Reclassification from accumulated other comprehensive income (loss)	1.0	1.0
March 31	(26.9)	(25.3)
Available-for-Sale Securities
Changes in Accumulated Other Comprehensive Income (Loss)
January 1	0.0	(0.3)
Cumulative effect of accounting change	0.0
Other comprehensive income (loss) before reclassifications	0.0	0.0
Reclassification from accumulated other comprehensive income (loss)	0.0	0.3
March 31	0.0	0.0
Defined Benefit Pension Plans and Postemployment Arrangements
Changes in Accumulated Other Comprehensive Income (Loss)
January 1	(69.3)	(88.4)
Cumulative effect of accounting change	(16.7)
Other comprehensive income (loss) before reclassifications	0.0	0.0
Reclassification from accumulated other comprehensive income (loss)	1.1	2.9
March 31	(84.9)	(85.5)
Foreign Currency Translation
Changes in Accumulated Other Comprehensive Income (Loss)
January 1	(1,136.9)	(848.0)
Cumulative effect of accounting change	0.0
Other comprehensive income (loss) before reclassifications	30.7	83.7
Reclassification from accumulated other comprehensive income (loss)	0.0	0.0
March 31	$ (1,106.2)	$ (764.3)

Tax Cuts and Jobs Act, Reclassification from AOCI to Retained Earnings, Tax Effect

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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

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

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