PPG's share of undistributed net earnings of equity affiliates.

No definition available.

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

- Definition

Percentage Of Ownership Interests

+ References

No definition available.

+ Details

Name:	ppg_PercentageOfOwnershipInterests
Namespace Prefix:	ppg_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Dividends received on equity and other investments during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3536-108585

+ Details

Name:	us-gaap_ProceedsFromDividendsReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ppg_InvestmentsInOtherOperatingJointVenturesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ppg_TaiwanChlorineIndustriesTCIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Investments (Additional Information) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Equity In Undistributed Earnings Losses Of Subsidiaries	$ 12	$ 7
Proceeds from Dividends Received	$ 8	$ 7	$ 77
Investments In Other Operating Joint Ventures [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Percentage Of Ownership Interests	50.00%
Taiwan Chlorine Industries (“TCI”) [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	40.00%