Condensed Consolidated Statement of Shareholders' Equity (Unaudited) Statement - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss	Total PPG	Non-controlling Interests
Beginning balance at Dec. 31, 2018	$ 4,732	$ 969	$ 788	$ 18,131	$ (12,958)	$ (2,300)	$ 4,630	$ 102
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the controlling and noncontrolling interests	317			312			312	5
Other comprehensive loss, net of tax	75					76	76	(1)
Cash dividends	(113)			(113)			(113)
Purchase of treasury stock	(175)				(175)		(175)
Issuance of treasury stock	184		121		63		184
Stock-based compensation activity	(10)		(10)				(10)
Ending balance at Mar. 31, 2019	5,010	969	899	18,330	(13,070)	(2,224)	4,904	106
Beginning balance at Dec. 31, 2019	5,403	969	950	18,906	(13,191)	(2,350)	5,284	119
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the controlling and noncontrolling interests	248			243			243	5
Other comprehensive loss, net of tax	(702)					(692)	(692)	(10)
Cash dividends	(120)			(120)			(120)
Issuance of treasury stock	16		12		4		16
Stock-based compensation activity	(8)		(8)				(8)
Ending balance at Mar. 31, 2020	$ 4,837	$ 969	$ 954	$ 19,029	$ (13,187)	$ (3,042)	$ 4,723	$ 114