Stock-Based Compensation (Additional Information) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants under the PPG Omnibus Plan	7,400,000
Stock-based compensation expense	$ 9	$ 9
Total income tax benefit recognized related to the stock-based compensation	$ 2	$ 2
Stock options granted from the PPG Omnibus Plan	588,870	517,433
Stock options granted from the PPG Omnibus Plan, weighted average fair value per share (in usd per share)	$ 22.50	$ 25.38
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	179,564	168,432
RSUs granted, weighted average fair value per share (in usd per share)	$ 103.35	$ 110.28
Award vesting period (in years)	3 years
Stock Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs granted	51,850	49,278
RSUs granted, weighted average fair value per share (in usd per share)	$ 109.74	$ 116.32
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
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 unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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- 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.

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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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- Definition

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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- Definition

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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