Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income attributable to controlling and noncontrolling interests	$ 375	$ 501	$ 715	$ 843
Other comprehensive (loss) income, net of tax:
Defined benefit pension and other postretirement benefits	15	(55)	(52)	(34)
Unrealized foreign currency translation adjustments	(297)	82	(174)	361
Derivative financial instruments	2	(4)	0	(17)
Other comprehensive (loss) income, net of tax	(280)	23	(226)	310
Total comprehensive income	95	524	489	1,153
Less: amounts attributable to noncontrolling interests:
Net income	(4)	(5)	(10)	(10)
Unrealized foreign currency translation adjustments	10	(6)	8	(13)
Comprehensive income attributable to PPG	$ 101	$ 513	$ 487	$ 1,130