Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income attributable to controlling and noncontrolling interests	$ 382	$ 616	$ 1,097	$ 1,459
Other comprehensive (loss) income, net of tax:
Defined benefit pension and other postretirement benefits	(12)	(29)	(64)	(63)
Unrealized foreign currency translation adjustments	89	26	(85)	387
Derivative financial instruments	(2)	1	(2)	(16)
Other comprehensive income (loss), net of tax	75	(2)	(151)	308
Total comprehensive income	457	614	946	1,767
Less: amounts attributable to noncontrolling interests:
Net income	(4)	(6)	(14)	(16)
Unrealized foreign currency translation adjustments	3	(2)	11	(15)
Comprehensive income attributable to PPG	$ 456	$ 606	$ 943	$ 1,736