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)/Income	Total PPG	Non-controlling Interests
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 income, 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
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	348
Other comprehensive income, net of tax	(583)
Ending balance at Jun. 30, 2020	4,938	969	962	19,010	(13,184)	(2,925)	4,832	106
Beginning balance at Mar. 31, 2020	4,837	969	954	19,029	(13,187)	(3,042)	4,723	114
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the controlling and noncontrolling interests	100			102			102	(2)
Other comprehensive income, net of tax	119					117	117	2
Cash dividends	(121)			(121)			(121)
Issuance of treasury stock	5		2		3		5
Stock-based compensation activity	6		6				6
Dividends paid on subsidiary common stock to noncontrolling interests	(3)							(3)
Reductions in noncontrolling interests	(5)							(5)
Ending balance at Jun. 30, 2020	4,938	969	962	19,010	(13,184)	(2,925)	4,832	106
Beginning balance at Dec. 31, 2020	5,815	969	1,008	19,469	(13,158)	(2,599)	5,689	126
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the controlling and noncontrolling interests	385			378			378	7
Other comprehensive income, net of tax	(133)					(131)	(131)	(2)
Cash dividends	(128)			(128)			(128)
Issuance of treasury stock	35		25		10		35
Stock-based compensation activity	(4)		(4)				(4)
Reductions in noncontrolling interests	(1)							(1)
Ending balance at Mar. 31, 2021	5,969	969	1,029	19,719	(13,148)	(2,730)	5,839	130
Beginning balance at Dec. 31, 2020	5,815	969	1,008	19,469	(13,158)	(2,599)	5,689	126
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the controlling and noncontrolling interests	818
Other comprehensive income, net of tax	(68)
Ending balance at Jun. 30, 2021	6,411	969	1,053	20,022	(13,138)	(2,664)	6,242	169
Beginning balance at Mar. 31, 2021	5,969	969	1,029	19,719	(13,148)	(2,730)	5,839	130
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the controlling and noncontrolling interests	433			431			431	2
Other comprehensive income, net of tax	65					66	66	(1)
Cash dividends	(128)			(128)			(128)
Issuance of treasury stock	27		17		10		27
Stock-based compensation activity	7		7				7
Dividends paid on subsidiary common stock to noncontrolling interests	(4)							(4)
Noncontrolling Interest, Increase from Business Combination	50							50
Reductions in noncontrolling interests	(8)							(8)
Ending balance at Jun. 30, 2021	$ 6,411	$ 969	$ 1,053	$ 20,022	$ (13,138)	$ (2,664)	$ 6,242	$ 169