Consolidated Statement of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive (Loss)/Income	Total PPG	Non-controlling Interests
Beginning balance at Dec. 31, 2016	$ 4,915	$ 969	$ 707	$ 15,980	$ (10,472)	$ (2,356)	$ 4,828	$ 87
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the controlling and noncontrolling interests	1,615			1,594			1,594	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
Dividends paid on subsidiary common stock to noncontrolling interests	(5)							(5)
Reductions in noncontrolling interests	(5)							(5)
Ending balance at Dec. 31, 2017	5,672	969	756	17,140	(11,251)	(2,057)	5,557	115
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the controlling and noncontrolling interests	1,358			1,341			1,341	17
Other comprehensive loss, net of tax	(147)					(136)	(136)	(11)
Cash dividends	(453)			(453)			(453)
Purchase of treasury stock	(1,721)				(1,721)		(1,721)
Issuance of treasury stock	42		28		14		42
Stock-based compensation activity	4		4				4
Dividends paid on subsidiary common stock to noncontrolling interests	(7)							(7)
Reductions in noncontrolling interests	(12)		0				0	(12)
Reclassifications of Temporary to Permanent Equity				107		(107)
Ending 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]
Cumulative Effect of New Accounting Principle in Period of Adoption	(4)	0	0	(4)	0	0	(4)	0
Net income attributable to the controlling and noncontrolling interests	1,269			1,243			1,243	26
Other comprehensive loss, net of tax	(51)					(50)	(50)	(1)
Cash dividends	(468)			(468)			(468)
Purchase of treasury stock	(325)				(325)		(325)
Issuance of treasury stock	243		151		92		243
Stock-based compensation activity	10		10				10
Dividends paid on subsidiary common stock to noncontrolling interests	(8)							(8)
Reclassifications of Temporary to Permanent Equity	0	0	0		0		0	0
Stockholders' Equity, Other	1	0	1	0	0	0	1	0
Ending balance at Dec. 31, 2019	$ 5,403	$ 969	$ 950	$ 18,906	$ (13,191)	$ (2,350)	$ 5,284	$ 119