Fair Value Measurements and Risk - Derivative Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Asset Derivatives
Total derivatives	$ 6.3	$ 3.7
Liability Derivatives
Total derivatives	6.2	14.9
Other current assets
Asset Derivatives
Total derivatives	21.2	21.4
Currency contracts | Derivatives designated as hedging instruments under ASC 815: | Other current assets
Asset Derivatives
Total derivatives	2.7	2.4
Liability Derivatives
Total derivatives	(3.1)	(2.9)
Currency contracts | Derivatives designated as hedging instruments under ASC 815: | Other assets
Asset Derivatives
Total derivatives	2.6	1.3
Currency contracts | Derivatives designated as hedging instruments under ASC 815: | Other liabilities
Liability Derivatives
Total derivatives	7.4	12.9
Currency contracts | Derivatives not designated as hedging instruments under ASC 815: | Other current assets
Asset Derivatives
Total derivatives	0.5	0.0
Liability Derivatives
Total derivatives		(0.1)
Currency contracts | Derivatives not designated as hedging instruments under ASC 815: | Other current liabilities
Asset Derivatives
Total derivatives	(0.3)
Liability Derivatives
Total derivatives	0.0	0.6
Currency contracts | Derivatives not designated as hedging instruments under ASC 815: | Other liabilities
Liability Derivatives
Total derivatives	0.0
Interest rate contracts | Derivatives designated as hedging instruments under ASC 815: | Other current assets
Asset Derivatives
Total derivatives	0.0	0.0
Interest rate contracts | Derivatives designated as hedging instruments under ASC 815: | Other assets
Asset Derivatives
Total derivatives	0.0	0.0
Interest rate contracts | Derivatives designated as hedging instruments under ASC 815: | Other current liabilities
Liability Derivatives
Total derivatives	0.3	0.1
Interest rate contracts | Derivatives designated as hedging instruments under ASC 815: | Other liabilities
Liability Derivatives
Total derivatives	1.6	0.7
Variable-to-fixed cross-currency derivatives | Derivatives designated as hedging instruments under ASC 815: | Other current assets
Asset Derivatives
Total derivatives	14.6	0.0
Liability Derivatives
Total derivatives		(15.4)
Variable-to-fixed cross-currency derivatives | Derivatives designated as hedging instruments under ASC 815: | Other assets
Asset Derivatives
Total derivatives		0.0
Variable-to-fixed cross-currency derivatives | Derivatives designated as hedging instruments under ASC 815: | Other current liabilities
Liability Derivatives
Total derivatives	0.0
Variable-to-fixed cross-currency derivatives | Derivatives designated as hedging instruments under ASC 815: | Other liabilities
Asset Derivatives
Total derivatives	(13.8)
Liability Derivatives
Total derivatives	$ 0.0	$ 19.0