Income Taxes (Additional Information) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) subsidiary jurisdiction	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Income Taxes [Line Items]
U.S. federal income tax rate	21.00%	21.00%	21.00%
Deferred income taxes	$ 35	$ (47)	$ (5)
Income before income taxes of non-US operations	1,815	1,362	1,661
Net operating loss carryforwards	183	193
Deferred Tax Assets, Tax Credit Carryforwards, Other	115	119
Unrecognized tax benefits that would affect the effective tax rate, if recognized	132
Accrued estimated interest and penalties on unrecognized tax benefits	17	18	17
Recognized (income) expense for estimated interest and penalties	(2)	2	1
Undistributed Earnings of Foreign Subsidiaries	$ 4,300	4,100
Number of taxable jurisdictions | jurisdiction	80
Number of PPG Subsidiaries | subsidiary	280
Income Tax, Potential U.S. Tax Cost for Repatriation of Foreign Earnings	$ 39	40
U.S.
Income Taxes [Line Items]
Deferred income taxes	66	30	22
Income before income taxes of non-US operations	469	190	596
Non United States
Income Taxes [Line Items]
Income before income taxes of non-US operations	1,346	1,172	$ 1,065
Net Operating Loss, Indefinite Life
Income Taxes [Line Items]
Net operating loss carryforwards	106	113
Net Operating Loss, Expiring Within 20 Years
Income Taxes [Line Items]
Net operating loss carryforwards	$ 77	$ 80