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:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 16
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3337-108585

+ Details

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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

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

- Details

Name:	us-gaap_InvestmentTypeAxis=ppg_InvestmentsInAndAdvancesToAffiliatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=ppg_MarketableSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=ppg_TradingSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_OtherInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
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- Details

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Investments (Detail) - USD ($) $ in Millions	12 Months Ended
Investments (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt and Equity Securities, FV-NI [Line Items]
Investments	$ 274	$ 267
Equity in undistributed earnings losses of subsidiaries	15	8	$ 11
Proceeds from dividends received	9	18	$ 15
Investments in equity affiliates
Debt and Equity Securities, FV-NI [Line Items]
Investments	126	120
Marketable equity securities (See Note 10) \| Trading Securities
Debt and Equity Securities, FV-NI [Line Items]
Investments	98	97
Other
Debt and Equity Securities, FV-NI [Line Items]
Investments	$ 50	$ 50
Investments In Other Operating Joint Venture \| Minimum
Debt and Equity Securities, FV-NI [Line Items]
Percentage of ownership interests	20.00%
Investments In Other Operating Joint Venture \| Maximum
Debt and Equity Securities, FV-NI [Line Items]
Percentage of ownership interests	50.00%