Condensed Consolidated Statement of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income attributable to controlling and noncontrolling interests	$ 448	$ 373	$ 796	$ 969
Other comprehensive income/(loss), net of tax:
Defined benefit pension and other postretirement benefits	3	(2)	9	4
Unrealized foreign currency translation adjustments	136	(103)	(453)	(37)
Derivative financial instruments	0	1	0	0
Other comprehensive income/(loss), net of tax	139	(104)	(444)	(33)
Total comprehensive income	587	269	352	936
Less: amounts attributable to noncontrolling interests:
Net income	(6)	(6)	(9)	(18)
Unrealized foreign currency translation adjustments	(2)	6	6	5
Comprehensive income attributable to PPG	$ 579	$ 269	$ 349	$ 923