Long-term Employee Benefits - Schedule of Defined Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amounts recognized in the consolidated balance sheets consist of:
Accrued pensions	$ (261.9)	$ (279.1)
Pension Plan [Member]
Change in benefit obligation:
Projected benefit obligation at beginning of year	636.9	547.6
Service cost	8.8	9.0	$ 10.7
Interest cost	13.1	13.8	15.1
Participant contributions	1.3	1.3
Actuarial gains, net	(3.3)	(13.8)
Plan curtailments, settlements and special termination benefits	(19.4)	(12.9)
Benefits paid	(25.6)	(23.3)
Business combinations and other adjustments	0.7	51.2
Foreign currency translation	(28.8)	64.0
Projected benefit obligation at end of year	583.7	636.9	547.6
Change in plan assets:
Fair value of plan assets at:	365.0	288.7
Actual return on plan assets	(1.4)	22.2
Employer contributions	24.6	27.4
Participant contributions	1.3	1.3
Benefits paid	25.6	23.3
Settlements	(12.5)	(13.9)
Business combinations and other adjustments	(0.1)	(32.4)
Foreign currency translation	(19.0)	30.2
Fair value of plan assets at:	332.3	365.0	$ 288.7
Funded status, net	(251.4)	(271.9)
Amounts recognized in the consolidated balance sheets consist of:
Other assets	22.0	19.2
Other accrued liabilities	(11.5)	(12.0)
Accrued pensions	(261.9)	(279.1)
Net amount recognized	$ (251.4)	$ (271.9)

Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

Name:	us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.