Commitments and Contingent Liabilities (Accretion Of Future Funding Obligation) (Detail) (Pittsburgh Corning Corporation, Asbestos Issue, USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Pittsburgh Corning Corporation \| Asbestos Issue
Accretion For Liability Settlement [Line Items]
Accretion of asbestos liability 2013	$ 14
Accretion of asbestos liability 2014	14
Accretion of asbestos liability 2015-2023	81
Accretion of asbestos liability	$ 109

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

No definition available.

Name:	ppg_AccretionOfInterestOnLitigationSettlements
Namespace Prefix:	ppg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration