Shareholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 5,672	$ 4,915	$ 4,915
Net income	340	342	342
Other comprehensive income, net of tax	54	287
Reclassifications of Temporary to Permanent Equity	107
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	6	20
Cash dividends	(112)	(103)
Issuance of treasury stock	31	34
Purchase of treasury stock	(600)	(163)
Stock-based compensation activity	(19)	(21)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	(6)	(5)
Ending balance	5,467	5,286	5,672
Total PPG Shareholders' Equity [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	5,557	4,828	4,828
Net income	334	337
Other comprehensive income, net of tax	52	280
Reclassifications of Temporary to Permanent Equity	107
Cash dividends	(112)	(103)
Issuance of treasury stock	31	34
Purchase of treasury stock	(600)	(163)
Stock-based compensation activity	(19)	(21)
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	(4)	0
Ending balance	5,346	5,192	5,557
Non-controlling Interests [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	115	87	87
Net income	6	5
Other comprehensive income, net of tax	2	7
Reclassifications of Temporary to Permanent Equity	0
Cash dividends	0	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	(2)	(5)
Ending balance	$ 121	$ 94	$ 115