Summary of Significant Accounting Policies New Accounting Standards (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2019	[1]	Jan. 01, 2019	Mar. 31, 2018	[2]	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principle				$ 0.0			$ 2.2
Net cash provided by operating activities	$ 368.6	$ 364.1	$ 296.4
Net Cash Provided by (Used in) Financing Activities	(38.0)	93.4	587.3
Effect of exchange rate changes on cash and cash equivalents	(8.1)	(32.2)	(0.9)
Right-of-use assets, net	270.3	$ 0.0
Lease liabilities	$ 284.3
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principle				$ 28.8			$ 3.3
Accounting Standards Update 2014-09 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principle									$ 1.5
Accounting Standards Update 2016-01 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principle									1.1
Accounting Standards Update 2016-16 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principle									$ 0.7
Accounting Standards Update 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities			44.3
Net Cash Provided by (Used in) Financing Activities			1.5
Effect of exchange rate changes on cash and cash equivalents			$ 11.3
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets, net						$ 310.1
Lease liabilities						$ 320.3

[1] Effective January 1, 2019, we adopted the provisions of ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. We recognized a cumulative effect adjustment to January 1, 2019 retained earnings as a result of adopting this standard. See Note 1 for further details.

[2] Effective January 1, 2018, we adopted the provisions of ASU 2014-09, Revenue From Contracts with Customers, ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, and ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory. We recognized a cumulative effect adjustment to January 1, 2018 retained earnings as a result of adopting each of these standards. See Note 1 for further details of the impact of each standard.