Debt (Details) (USD $)	9 Months Ended
Sep. 30, 2011
Debt (Textuals) [Abstract]
Additional borrowing capacity	$ 979,000,000
Absorption of reduction to shareholders' equity to remain in compliance with covenant	527,000,000
Financial covenants	2
Borrowings under Five Year Revolving Credit Agreement	0
Principal amount of Zero Coupon Convertible Senior Notes	0
Principal amount of Zero Coupon Convertible Senior Notes due 2031	108,100,000
Accreted value principal amount of Zero Coupon Convertible Senior Notes	58,100,000
Zero Coupon Convertible Senior Notes due 2031 [Member]
Short-term Debt [Line Items]
Repurchase of senior notes for cash	$ 57,900,000

Absorption of reduction to shareholders' equity to remain in compliance with covenant.

Name:	mas_AbsorptionOfReductionToShareholdersEquityToRemainInComplianceWithCovenant
Namespace Prefix:	mas
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Accreted value principal amount of Zero Coupon Convertible Senior Notes.

+ Details

Name:	mas_AccretedValuePrincipalAmountOfZeroCouponConvertibleSeniorNotes
Namespace Prefix:	mas
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument Principal at Maturity.

+ Details

Name:	mas_DebtInstrumentPrincipalAtMaturity
Namespace Prefix:	mas
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Textuals.

+ Details

Name:	mas_DebtTextualsAbstract
Namespace Prefix:	mas
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Financial covenants.

+ Details

Name:	mas_FinancialCovenants
Namespace Prefix:	mas
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Line Of Credit Facility Increase Additional Borrowing.

+ Details

Name:	mas_LineOfCreditFacilityIncreaseAdditionalBorrowing
Namespace Prefix:	mas
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow for a debt where holder has highest claim on the entity's asset in case of bankruptcy or liquidation during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 18

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 20

-Subparagraph b

+ Details

Name:	us-gaap_RepaymentsOfSeniorDebt
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Senior note holders are paid off in full before any payments are made to junior note holders.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

+ Details

Name:	us-gaap_SeniorLongTermNotes
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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.

+ Details

Name:	us-gaap_ShortTermDebtLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration