Employee Savings Plan (Additional Information) (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Employee Benefits and Share-based Compensation [Abstract]
Company-matching contributions are applied to eligible participant compensation	6.00%	6.00%	6.00%
Company-matching contribution	50.00%		75.00%
Compensation expense related to the ESOP		$ 28	$ 26	$ 9
Discontinued Operations - Employee Stock Ownership Plan (ESOP), Compensation Expense		5	4	1
Deductible dividends on PPG shares held by the ESOP		$ 18	$ 20	$ 24

Percent of planned Company-match contributed by the Company.

No definition available.

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- Definition

Company matching contribution percentage for Defined Contribution Plan.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Discontinued Operations - Employee Stock Ownership Plan (ESOP), Compensation Expense

+ References

No definition available.

+ Details

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Namespace Prefix:	ppg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of plan compensation cost recognized during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 40

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

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

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 93-6

-Paragraph 53

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Dividends paid on stock held by an employee stock ownership plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 40

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

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

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 93-6

-Paragraph 53

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration