Shareholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 5,672	$ 4,915
Net income	$ 375	$ 501	715	843
Other comprehensive income, net of tax	(280)	23	(226)	310
Reclassifications of Temporary to Permanent Equity			107
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			9	21
Cash dividends			(224)	(205)
Issuance of treasury stock			33	49
Purchase of treasury stock			(1,063)	(163)
Stock-based compensation activity			(12)	(16)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests			(19)	(5)
Ending balance	4,983	5,728	4,983	5,728
Total PPG Shareholders' Equity [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			5,557	4,828
Net income			705	833
Other comprehensive income, net of tax			(218)	297
Reclassifications of Temporary to Permanent Equity			107
Cash dividends			(222)	(205)
Issuance of treasury stock			33	49
Purchase of treasury stock			(1,063)	(163)
Stock-based compensation activity			(12)	(16)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests			(3)	0
Ending balance	4,884	5,623	4,884	5,623
Non-controlling Interests [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			115	87
Net income			10	10
Other comprehensive income, net of tax			(8)	13
Reclassifications of Temporary to Permanent Equity			0
Cash dividends			(2)	0
Issuance of treasury stock			0	0
Purchase of treasury stock			0	0
Stock-based compensation activity			0	0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests			(16)	(5)
Ending balance	$ 99	$ 105	$ 99	$ 105