Condensed Consolidated Statement of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income attributable to controlling and noncontrolling interests	$ 373	$ 382	$ 969	$ 1,097
Other comprehensive (loss)/income, net of tax:
Defined benefit pension and other postretirement benefits	(2)	(12)	4	20
Unrealized foreign currency translation adjustments	(103)	89	(37)	(62)
Derivative financial instruments	1	(2)	0	(2)
Other comprehensive (loss)/income, net of tax	(104)	75	(33)	(44)
Total comprehensive income	269	457	936	1,053
Less: amounts attributable to noncontrolling interests:
Net income	(6)	(4)	(18)	(14)
Unrealized foreign currency translation adjustments	6	3	5	11
Comprehensive income attributable to PPG	$ 269	$ 456	$ 923	$ 1,050