Employee Benefit Plans (Employee Savings Plan) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Compensation and Retirement Disclosure [Abstract]
Company-matching contributions are applied to eligible participant compensation	6.00%	6.00%	6.00%
Company-matching contribution	100.00%	100.00%	75.00%
Compensation expense related to the ESOP	$ 42	$ 36	$ 28
Deductible dividends on PPG shares held by the ESOP	$ 14	$ 15	$ 18

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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- Details

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Data Type:	xbrli:stringItemType
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- 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

+ 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

+ Details

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