Commitments and Contingent Liabilities (Additional Information) (Detail) $ in Millions	1 Months Ended	12 Months Ended				48 Months Ended
	May 14, 2002 shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) Location sites	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2011 Location	Dec. 31, 2008 USD ($)	Sep. 30, 2008 Location
Commitments and Contingencies Disclosure [Line Items]
Interest Penalty Asserted by a Foreign Tax Authority			$ 70
Asbestos [Abstract]
Obligation reported as a current liability			0	$ 796
Obligation reported as a non-current liability			0	252
Environmental Matters [Abstract]
Reserves for environmental contingencies			285	233
Reserves for environmental contingencies classified as current liabilities			76	51
Cash outlays related to environmental remediation			47	109	$ 165
Pretax charges for environmental remediation costs			94	9	144
Historical low end of range of annual environmental remediation expense over the past 15 years			8
Historical high end of range of annual environmental remediation expense over the past 15 years			$ 34
Remediation Period			10 years
Sewer Sites - Responsibility for Remedial Activity is Shared | sites			10
Unfinished Environmental Remediation [Member]
Environmental Matters [Abstract]
Number Of Sites Involved For Environmental Remediation | Location			7
Maximum
Environmental Matters [Abstract]
Unreserved loss contingencies related to environmental matters, high estimate			$ 200
Minimum
Environmental Matters [Abstract]
Unreserved loss contingencies related to environmental matters, high estimate			100
Asbestos Issue
Asbestos [Abstract]
Other Reserves			162
Pittsburgh Corning Corporation [Member] | Asbestos Issue
Asbestos [Abstract]
Agreement to convey assets to the PC asbestos settlement trust (the Trust), shares of PPG common stock | shares	2,777,778
Future PPG cash payments to the Trust, prepayment discount rate	5.50%
Future cash payments to the Trust by PPG's participating historical insurance carriers								$ 1,700
Scenario, Forecast | Maximum
Environmental Matters [Abstract]
Cash For Environmental Loss Contingencies High Estimate		$ 70				$ 50
Scenario, Forecast | Minimum
Environmental Matters [Abstract]
Cash For Environmental Loss Contingencies Low Estimate		$ 50				$ 25
Jersey City Manufacturing Plant
Environmental Matters [Abstract]
Reserves for environmental contingencies			163	133
Pretax charges for environmental remediation costs			60	0	136
Legacy Glass and Chemical Sites [Member]
Environmental Matters [Abstract]
Reserves for environmental contingencies			70	48
Other Environmental Contingencies [Member]
Environmental Matters [Abstract]
Reserves for environmental contingencies			52	52
Pretax charges for environmental remediation costs			$ 34	$ 9	$ 8
Administrative Content Order Nineteen Ninety Aco [Member]
Environmental Matters [Abstract]
Number Of Sites Involved For Environmental Remediation | Location			61
Administrative Content Order Nineteen Ninety Aco [Member] | Finished Environmental Remediation [Member]
Environmental Matters [Abstract]
Number Of Sites Involved For Environmental Remediation | Location			47
Administrative Content Order Nineteen Ninety Aco [Member] | Unfinished Environmental Remediation [Member]
Environmental Matters [Abstract]
Number Of Sites Involved For Environmental Remediation | Location			14
Orphan Sites Settlement
Environmental Matters [Abstract]
Number of sites | Location			6
Other Contingency Matters [Abstract]
Number of sites | Location			6
Orphan Sites Settlement | Unfinished Environmental Remediation [Member]
Environmental Matters [Abstract]
Number Of Sites Involved For Environmental Remediation | Location									6
New Jersey Remediation Sites [Member] | Unfinished Environmental Remediation [Member]
Environmental Matters [Abstract]
Number Of Sites Involved For Environmental Remediation			6
Judicial Consent Order [Member]
Environmental Matters [Abstract]
Number Of Sites Involved For Environmental Remediation | Location							20
Soil Treatment Transportation And Disposal Of Excavated Soil [Member]
Environmental Matters [Abstract]
Percentage of the total remaining reserve			28.00%
Construction Services [Member]
Environmental Matters [Abstract]
Percentage of the total remaining reserve			29.00%