Long-term Employee Benefits - Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets (Details) - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Change in plan assets:
Fair value of plan assets at:	$ 158.0	$ 77.5
Realized (loss)	0.0	0.0
Change in unrealized gain	(4.2)	9.9
Purchases, sales, issues and settlements	(2.1)	70.6
Transfers in/(out) of Level 3	0.0	0.0
Fair value of plan assets at:	151.7	158.0
Private Equity Funds [Member]
Change in plan assets:
Fair value of plan assets at:	135.7	64.1
Realized (loss)	0.0	0.0
Change in unrealized gain	(4.4)	8.3
Purchases, sales, issues and settlements	(4.4)	63.3
Transfers in/(out) of Level 3	0.0	0.0
Fair value of plan assets at:	126.9	135.7
Debt and Equity [Member]
Change in plan assets:
Fair value of plan assets at:	8.8	2.2
Realized (loss)	0.0	0.0
Change in unrealized gain	(0.2)	0.4
Purchases, sales, issues and settlements	2.6	6.2
Transfers in/(out) of Level 3	0.0	0.0
Fair value of plan assets at:	11.2	8.8
Real Estate [Member]
Change in plan assets:
Fair value of plan assets at:	13.5	11.2
Realized (loss)	0.0	0.0
Change in unrealized gain	0.4	1.2
Purchases, sales, issues and settlements	(0.3)	1.1
Transfers in/(out) of Level 3	0.0	0.0
Fair value of plan assets at:	$ 13.6	$ 13.5

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets sold.

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets still held.

+ References

+ Details

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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- Definition

Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(iv)(01)
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
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-Section 50
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
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-URI http://asc.fasb.org/extlink&oid=112275985&loc=d3e4179-114921

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

+ Details

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- Definition

Amount, measured using unobservable input, of increase (decrease) in plan asset of defined benefit plan from purchase, sale and settlement of trade associated with underlying investment.

+ References

+ Details

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan, for assets transferred into (out of) Level 3 of fair value hierarchy. Includes, but is not limited to, transfer due to change in observability of significant inputs.

+ References

+ Details

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