Consolidated Statement of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income/(Loss)	Total PPG	Non-controlling Interests
Beginning balance at Dec. 31, 2014	$ 5,265	$ 484	$ 1,028	$ 14,498	$ (8,714)	$ (2,116)	$ 5,180	$ 85
Net income attributable to the controlling and noncontrolling interests	1,427			1,406			1,406	21
Other comprehensive loss, net of tax	(599)					(586)	(586)	(13)
Cash dividends	(383)			(383)			(383)
Adjustments to Additional Paid in Capital, Stock Split	0	485	(485)	0	0	0	0	0
Purchase of treasury stock	(751)				(751)		(751)
Issuance of treasury stock	71		46		25		71
Stock-based compensation activity	46		46				46
Dividends paid on subsidiary common stock to noncontrolling interests	(4)							(4)
Reductions in noncontrolling interests	(3)							(3)
Ending balance at Dec. 31, 2015	5,069	969	635	15,521	(9,440)	(2,702)	4,983	86
Net income attributable to the controlling and noncontrolling interests	899			877			877	22
Other comprehensive loss, net of tax	336					346	346	(10)
Cash dividends	(414)			(414)			(414)
Purchase of treasury stock	(1,050)				(1,050)		(1,050)
Issuance of treasury stock	55		37		18		55
Stock-based compensation activity	29		29				29
Dividends paid on subsidiary common stock to noncontrolling interests	(4)							(4)
Reductions in noncontrolling interests	(7)		0				0	(7)
Ending balance at Dec. 31, 2016	4,913	969	701	15,984	(10,472)	(2,356)	4,826	87
Net income attributable to the controlling and noncontrolling interests	1,612			1,591			1,591	21
Other comprehensive loss, net of tax	316					299	299	17
Cash dividends	(434)			(434)			(434)
Purchase of treasury stock	(813)				(813)		(813)
Issuance of treasury stock	83		49		34		83
Stock-based compensation activity	6		6				6
Dividends paid on subsidiary common stock to noncontrolling interests	(5)							(5)
Reductions in noncontrolling interests	(5)		0				0	(5)
Ending balance at Dec. 31, 2017	$ 5,673	$ 969	$ 756	$ 17,141	$ (11,251)	$ (2,057)	$ 5,558	$ 115