Fair Value Measurements - Defined Benefit Plan Assets (Details) - Pension Plan [Member] - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
United States
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 240.1	$ 229.5	$ 235.8
United States | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	240.1	229.5
United States | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	34.7	65.6
United States | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0.4	0.5
United States | Fixed Income Securities [Member] | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	127.1	113.8
United States | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	86.7	94.2
United States | Real estate and other | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	26.3	21.5
United States | Market Approach Valuation Technique [Member] | Fixed Income Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1.3	15.3
United States | Market Approach Valuation Technique [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	13.5	37.2
United States | Market Approach Valuation Technique [Member] | Real estate and other | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	19.9	13.1
United States | Market Approach Valuation Technique [Member] | Real estate and other | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0.4	0.5
United States | Net Asset Value [Member] | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	205.0	163.4
United States | Net Asset Value [Member] | Fixed Income Securities [Member] | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	125.8	98.5
United States | Net Asset Value [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	73.2	57.0
United States | Net Asset Value [Member] | Real estate and other | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	6.0	7.9
Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	483.4	393.8	$ 395.1
Non-US [Member] | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	483.4	393.8
Non-US [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	105.4	87.1
Non-US [Member] | Fixed Income Securities [Member] | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	212.4	183.4
Non-US [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	233.9	190.8
Non-US [Member] | Real estate and other | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	37.1	19.6
Non-US [Member] | Market Approach Valuation Technique [Member] | Fixed Income Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets
Non-US [Member] | Market Approach Valuation Technique [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	105.4	87.1
Non-US [Member] | Net Asset Value [Member] | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	378.0	306.7
Non-US [Member] | Net Asset Value [Member] | Fixed Income Securities [Member] | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	212.4	183.4
Non-US [Member] | Net Asset Value [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	128.5	103.7
Non-US [Member] | Net Asset Value [Member] | Real estate and other | Fair Value, Measurements, Recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 37.1	$ 19.6