Segment Information Level 4 (Details) - Reconciliation of Segment EBITDA to Net Income (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Asset impairment Charges	$ 5us-gaap_AssetImpairmentCharges	$ 5us-gaap_AssetImpairmentCharges	$ 124us-gaap_AssetImpairmentCharges	$ 23us-gaap_AssetImpairmentCharges
Asset and goodwill impairment		(5)msc_Assetandgoodwillimpairment	(181)msc_Assetandgoodwillimpairment	(23)msc_Assetandgoodwillimpairment
Business realignment costs		(47)msc_BusinessRealignmentCostsAddBack	(21)msc_BusinessRealignmentCostsAddBack	(35)msc_BusinessRealignmentCostsAddBack
Integration costs		0	(10)	(12)
Unrealized and realized foreign currency losses excluded from EBITDA		(32)	(2)	(3)
Other		(25)us-gaap_OtherExpenses	(35)us-gaap_OtherExpenses	(39)us-gaap_OtherExpenses
Loss on extinguishment of debt		0	(6)	0
Interest expense, net		308us-gaap_InterestExpense	303us-gaap_InterestExpense	263us-gaap_InterestExpense
Income tax (expense) benefit		(22)us-gaap_IncomeTaxExpenseBenefit	(379)us-gaap_IncomeTaxExpenseBenefit	410us-gaap_IncomeTaxExpenseBenefit
Depreciation and amortization		(144)	(148)	(153)
Net income		(223)us-gaap_NetIncomeLoss	(571)us-gaap_NetIncomeLoss	247us-gaap_NetIncomeLoss
Net Income (Loss) Attributable to Noncontrolling Interest		(1)	(1)	(1)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		(224)us-gaap_ProfitLoss	(572)us-gaap_ProfitLoss	246us-gaap_ProfitLoss
EPCD [Member]
Segment Reporting Information [Line Items]
Segment EBITDA [Line Items]		290	279	351
Depreciation and amortization		(101)	(105)	(109)
FPD [Member]
Segment Reporting Information [Line Items]
Segment EBITDA [Line Items]		255	235	205
Depreciation and amortization		(36)	(37)	(38)
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Segment EBITDA [Line Items]		(83)	(68)	(57)
Depreciation and amortization		$ (7)	$ (6)	$ (6)

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Business realignment costs - add back

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Segment EBITDA

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Unrealized and realized foreign currency losses excluded from EBITDA

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs.

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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Amount of Net Income (Loss) attributable to noncontrolling interest.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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