Income Taxes (Additional Information) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2025 USD ($) subsidiary	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Income Taxes [Line Items]
Effective income tax rate	22.40%	25.60%	25.30%
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	$ 258	$ 327
Undistributed earnings of foreign subsidiaries	$ 7,500
Number of PPG subsidiaries | subsidiary	220
Income tax, potential U.S. tax cost for repatriation of foreign earnings	$ 167
Unrecognized tax benefits that would affect the effective tax rate, if recognized	94
Domestic Tax Jurisdiction
Income Taxes [Line Items]
Income before income taxes of non-US operations	293	210	$ (129)
Non United States
Income Taxes [Line Items]
Income before income taxes of non-US operations	$ 1,752	$ 1,642	$ 1,819