Fair Value Measurements and Risk - Derivative Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Asset Derivatives
Total derivatives	$ 22.2	$ 3.7
Liability Derivatives
Total derivatives	4.4	14.9
Currency contracts | Derivatives designated as hedging instruments under ASC 815: | Other current assets
Asset Derivatives
Total derivatives	5.4	2.4
Liability Derivatives
Total derivatives		(2.9)
Currency contracts | Derivatives designated as hedging instruments under ASC 815: | Other assets
Asset Derivatives
Total derivatives	6.3	1.3
Currency contracts | Derivatives designated as hedging instruments under ASC 815: | Other current liabilities
Liability Derivatives
Total derivatives	0.0
Currency contracts | Derivatives designated as hedging instruments under ASC 815: | Other liabilities
Liability Derivatives
Total derivatives	0.0	12.9
Currency contracts | Derivatives not designated as hedging instruments under ASC 815: | Other current assets
Asset Derivatives
Total derivatives	0.0	0.0
Liability Derivatives
Total derivatives	(0.2)	(0.1)
Currency contracts | Derivatives not designated as hedging instruments under ASC 815: | Other current liabilities
Liability Derivatives
Total derivatives	0.5	0.6
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	1.0	0.1
Interest rate contracts | Derivatives designated as hedging instruments under ASC 815: | Other liabilities
Liability Derivatives
Total derivatives	3.1	0.7
Variable-to-fixed cross-currency swaps | Derivatives designated as hedging instruments under ASC 815: | Other current assets
Asset Derivatives
Total derivatives	10.9	0.0
Liability Derivatives
Total derivatives		(15.4)
Variable-to-fixed cross-currency swaps | Derivatives designated as hedging instruments under ASC 815: | Other assets
Asset Derivatives
Total derivatives		0.0
Variable-to-fixed cross-currency swaps | Derivatives designated as hedging instruments under ASC 815: | Other current liabilities
Liability Derivatives
Total derivatives	0.0
Variable-to-fixed cross-currency swaps | Derivatives designated as hedging instruments under ASC 815: | Other liabilities
Asset Derivatives
Total derivatives	(0.4)
Liability Derivatives
Total derivatives	$ 0.0	$ 19.0