Commitments and Contingent Liabilities (Litigation Settlements Disclosure) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended	108 Months Ended	12 Months Ended
Dec. 31, 2014	Dec. 31, 2014 LegalMatter	Dec. 31, 2013	Dec. 31, 2012
Unreserved loss contingencies related to environmental matters, low estimate	$ 75
Asbestos Issue
Loss Contingency Claims Settled Number		580
Loss Contingency, Number of Plaintiffs		320
Change in fair value:
Loss Contingency Claims in the Process of Being Settled		80
Loss Contingency Number of Claims not in the Process of Being Settled.		240
Loss Contingency Claims Being Litigated.	110	110
Asbestos Settlement Liability, Current
Beginning balance/Prior year activity	763		683	593
Change in fair value:
PPG stock	58		75	72
Equity forward instrument	0
Accretion of asbestos liability	0
Reclassification	0		5	18
Ending balance/Activity during year	821	821	763	683
Asbestos Settlement Liability, Long-term
Beginning balance/Prior year activity	245		237	241
Change in fair value:
PPG stock	0
Equity forward instrument	0
Accretion of asbestos liability	14		13	14
Reclassification	0		(5)	(18)
Ending balance/Activity during year	259	259	245	237
Equity Forward (Asset) Liability
Beginning balance/Prior year activity	(207)		(130)	(56)
Change in fair value:
PPG stock	0
Equity forward instrument	(60)		(77)	(74)
Accretion of asbestos liability	0
Reclassification	0
Ending balance/Activity during year	(267)	(267)	(207)	(130)
pre-tax Charge
Beginning balance/Prior year activity	11		12	12
Change in fair value:
PPG stock	58		75	72
Equity forward instrument	(60)		(77)	(74)
Accretion of asbestos liability	14		13	14
Reclassification	0
Ending balance/Activity during year	$ 12	12	$ 11	$ 12
Maximum \| Asbestos Issue
Premises Claims Percentage	2.00%	2.00%

Interest cost associated with litigation settlements due to recognition of initial liability at net present value.

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Forward Contract Indexed to Issuers Equity, Change In Fair Value Of Contract

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Long Term Obligations Reclassified as Short Term Obligations

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The number of Loss Contingency Claims pertaining to asbestos that are currently being Litigated.

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The number of claims in the process of being settled or otherwise resolved.

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Loss Contingency the Number of Claims not in the Process of Being Settled or otherwise resolved. A portion of these claims are being litigated.

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Change in fair value of PPG stock to be contributed to the Asbestos Trust.

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Premises Claims Percentage

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Low-end estimate of the reasonably possible loss exposure in excess of the amount accrued for remediation, site restoration, postclosure, monitoring commitments, or other exit costs associated with the sale, disposal or abandonment of a particular property resulting from unanticipated contamination of the assets.

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

-Publisher FASB

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-SubTopic 20

-Section S99

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Aggregate carrying amount of the estimated litigation liability for known or estimated probable loss from litigation, which may include attorneys' fees and other litigation costs.

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Number of claims settled.

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Number of plaintiffs that have filed claims pertaining to a loss contingency.

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