Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income attributable to the controlling and noncontrolling interests	$ 1,358	$ 1,615	$ 895
Unrealized foreign currency translation (losses)/gains	(155)	248	(476)
Defined benefit pension and other postretirement benefit adjustments	9	78	808
Unrealized (losses)/gains – derivative financial instruments	(1)	(10)	4
Other comprehensive (loss)/income, net of tax	(147)	316	336
Total comprehensive income	1,211	1,931	1,231
Less: amounts attributable to noncontrolling interests:
Net income	(17)	(21)	(22)
Unrealized foreign currency translation (losses)/gains	11	(17)	10
Comprehensive income attributable to PPG	$ 1,205	$ 1,893	$ 1,219