Pension Plans Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Compensation expense recognized for 401(k)	$ 52.0	$ 50.0	$ 26.0
NAV Per Share, Investment Redemption, Notice Period	90 days
Foreign Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service cost, before tax	$ 0.1
Unrecognized prior service cost, after tax	0.1
Unrecognized actuarial losses, before tax	95.0
Unrecognized actuarial losses, after tax	73.0
Future actuarial losses, before tax	4.0
Future actuarial losses, after tax	$ 3.0
Expected long-term return on plan assets	3.58%	4.19%
Employer contributions	$ 10.6	$ 10.7
Expected contributions in next fiscal year	$ 10.0
Minimum [Member] | Foreign Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term return on plan assets	1.75%	1.75%
Maximum [Member] | Foreign Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term return on plan assets	6.00%	6.00%