Debt Obligations Level 4 (Details) Debt Outstanding - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Synthetic Letter of Credit Facility	$ 47
ABL Facility [Domain]
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	320
Non-Affiliated Debt [Abstract]
Long-Term	0	$ 60
Due Within One Year	0	0
6.625% First Priority Senior Notes Due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Premium	4	6
Non-Affiliated Debt [Abstract]
Long-Term	1,554	1,556
Due Within One Year	0	0
10.00% First Priority Senior Notes Due 2020 [Member]
Non-Affiliated Debt [Abstract]
Long-Term	315	0
Due Within One Year	0	0
8.875% Senior Secured Notes Due 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount	2	3
Non-Affiliated Debt [Abstract]
Long-Term	995	1,197
Due Within One Year	0	0
9.00% Second-Priority Senior Secured Notes Due 2020 [Member]
Non-Affiliated Debt [Abstract]
Long-Term	574	574
Due Within One Year	0	0
9.2% Debentures Due 2021 [Member]
Non-Affiliated Debt [Abstract]
Long-Term	74	74
Due Within One Year	0	0
7.875% Debentures Due 2023 [Member]
Non-Affiliated Debt [Abstract]
Long-Term	189	189
Due Within One Year	0	0
8.375% Sinking Fund Debentures Due 2016 [Member]
Non-Affiliated Debt [Abstract]
Long-Term	0	20
Due Within One Year	0	20
Australia Facility Due 2014 [Member]
Non-Affiliated Debt [Abstract]
Long-Term	29	36
Due Within One Year	3	4
Affiliated Debt [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity	10
Brazilian Bank Loans [Member]
Non-Affiliated Debt [Abstract]
Long-Term	5	9
Due Within One Year	42	47
Capital Leases [Member]
Non-Affiliated Debt [Abstract]
Long-Term	9	8
Due Within One Year	1	1
Other [Member]
Non-Affiliated Debt [Abstract]
Long-Term	5	12
Due Within One Year	34	27
Unamortized debt issuance costs
Non-Affiliated Debt [Abstract]
Long-Term	(51)	(57)
Due Within One Year	0	0
Total non-affiliated debt [Member]
Non-Affiliated Debt [Abstract]
Long-Term	3,698	3,678
Due Within One Year	$ 80	$ 99

Affiliated Debt [Abstract]

No definition available.

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Period Type:	duration

- Definition

Non-Affiliated Debt [Abstract]

+ References

No definition available.

+ Details

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Namespace Prefix:	msc_
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Balance Type:	na
Period Type:	duration

- Definition

synthetic letter of credit facility

+ References

No definition available.

+ Details

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Namespace Prefix:	msc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of debt premium that was originally recognized at the issuance of the instrument that has yet to be amortized.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 20, 22
-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

- Details

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Namespace Prefix:
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Balance Type:
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- Details

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Balance Type:
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- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=msc_A8875SeniorSecuredNotesDue2018Member
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Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=msc_A900SecondPrioritySeniorSecuredNotesDue2020Member
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Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=msc_A92DebenturesDue2021Member
Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=msc_A7875DebenturesDue2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=msc_A8375SinkingFundDebenturesDue2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=msc_AustraliaFacilityDue2014Member
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=msc_BrazilianBankLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_CapitalLeaseObligationsMember
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- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_UnsecuredDebtMember
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- Details

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