Stock-Based Compensation (Additional Information) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants under the PPG Omnibus Plan	6,400,000
Stock-based compensation expense	$ 7	$ 9
Total income tax benefit recognized related to the stock-based compensation	$ 2	$ 2
Stock options granted from the PPG Omnibus Plan	659,835	588,870
Stock options granted from the PPG Omnibus Plan, weighted average fair value per share (in usd per share)	$ 21.93	$ 22.50
Maximum term of the outstanding stock options for the PPG Omnibus Plan and the PPG Stock Plan for certain employees	10 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs granted	182,276	179,564
RSUs granted, weighted average fair value per share (in usd per share)	$ 112.99	$ 103.35
Award vesting period (in years)	3 years
Stock Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs granted	54,648	51,850
RSUs granted, weighted average fair value per share (in usd per share)	$ 119.52	$ 109.74
Executive Officer Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period for recognizing compensation costs (in years)	3 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable period	36 months

Share-Based Compensation Arrangement By Share-Based Payment Award, Exercisable Period for Stock Options

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Amount of deferred tax expense from write-off of the deferred tax asset related to deductible stock options at exercise.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of noncash expense for share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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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.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Net number of share options (or share units) granted during the period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Weighted average remaining contractual term of exercisable stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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