Fair Value of Assets and Liabilities - Fair Value Measurements (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Document Period End Date	Jun. 30, 2017
Fair Value Transfers Between Levels Amount	$ 0.0
Fair value liabilities measured on recurring basis
Derivative Liability			$ 22.7
Fair Value, Measurements, Recurring [Member]
Fair value assets measured on recurring basis
Total	113.3	$ 88.2
Fair value liabilities measured on recurring basis
Total	37.5	23.1
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value assets measured on recurring basis
Total	85.8	72.6
Fair value liabilities measured on recurring basis
Total	8.9	8.5
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value assets measured on recurring basis
Total	27.5	15.6
Fair value liabilities measured on recurring basis
Total	28.6	14.6
Short-term investments | Certificates of deposit | Fair Value, Measurements, Recurring [Member]
Fair value assets measured on recurring basis
Fair value of investment assets	76.9	64.1
Short-term investments | Certificates of deposit | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value assets measured on recurring basis
Fair value of investment assets	76.9	64.1
Short-term investments | Certificates of deposit | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value assets measured on recurring basis
Fair value of investment assets	0.0	0.0
Securities and other investments | Interest rate swaps | Fair Value, Measurements, Recurring [Member]
Fair value assets measured on recurring basis
Derivative Asset	6.3	8.4
Securities and other investments | Interest rate swaps | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value assets measured on recurring basis
Derivative Asset	0.0	0.0
Securities and other investments | Interest rate swaps | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value assets measured on recurring basis
Derivative Asset	6.3	8.4
Securities and other investments | Assets held in rabbi trusts [Member] | Fair Value, Measurements, Recurring [Member]
Fair value assets measured on recurring basis
Assets held in rabbi trusts	8.9	8.5
Securities and other investments | Assets held in rabbi trusts [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value assets measured on recurring basis
Assets held in rabbi trusts	0.0	0.0
Other current assets | Foreign exchange forward contracts | Fair Value, Measurements, Recurring [Member]
Fair value assets measured on recurring basis
Derivative Asset	4.3	7.2
Other current assets | Foreign exchange forward contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value assets measured on recurring basis
Derivative Asset	0.0	0.0
Other current assets | Foreign exchange forward contracts | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value assets measured on recurring basis
Derivative Asset	4.3	7.2
Other current assets | Interest rate swaps | Fair Value, Measurements, Recurring [Member]
Fair value assets measured on recurring basis
Derivative Asset	0.6	0.0
Other current assets | Interest rate swaps | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value assets measured on recurring basis
Derivative Asset	0.0	0.0
Other current assets | Interest rate swaps | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value assets measured on recurring basis
Derivative Asset	0.6	0.0
Other current assets | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member]
Fair value assets measured on recurring basis
Derivative Asset	2.9	0.0
Other current assets | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value assets measured on recurring basis
Derivative Asset	0.0	0.0
Other current assets | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value assets measured on recurring basis
Derivative Asset	2.9	0.0
Other assets | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member]
Fair value assets measured on recurring basis
Derivative Asset	13.4	0.0
Other assets | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value assets measured on recurring basis
Derivative Asset	0.0	0.0
Other assets | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value assets measured on recurring basis
Derivative Asset	13.4	0.0
Other current liabilities | Foreign exchange forward contracts | Fair Value, Measurements, Recurring [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	5.4	7.7
Other current liabilities | Foreign exchange forward contracts | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	0.0	0.0
Other current liabilities | Foreign exchange forward contracts | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	5.4	7.7
Other current liabilities | Interest rate swaps | Fair Value, Measurements, Recurring [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	6.9	6.9
Other current liabilities | Interest rate swaps | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	0.0	0.0
Other current liabilities | Interest rate swaps | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	6.9	6.9
Other current liabilities | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	2.9	0.0
Other current liabilities | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	0.0	0.0
Other current liabilities | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	2.9	0.0
Other liabilities | Fair Value, Measurements, Recurring [Member]
Fair value liabilities measured on recurring basis
Deferred compensation	8.9	8.5
Other liabilities | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value assets measured on recurring basis
Assets held in rabbi trusts	8.9	8.5
Other liabilities | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value liabilities measured on recurring basis
Deferred compensation	0.0	0.0
Other liabilities | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	13.4	0.0
Other liabilities | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	0.0	0.0
Other liabilities | Currency Swap [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair value liabilities measured on recurring basis
Derivative Liability	$ 13.4	$ 0.0