Restatement of Previously Reported Consolidated Annual Financial Statements - Summary of Restatement - Statement of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended								6 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income attributable to the controlling and noncontrolling interests	$ 156	$ 616	$ 501	$ 342	$ 344	$ (179)	$ 376	$ 354	$ 843	$ 1,459	$ 1,615	$ 895	$ 1,427
Unrealized foreign currency translation gains/(losses)		(29)	(55)	21					(34)	(63)	248	(476)	(717)
Defined benefit pension and other postretirement benefit adjustments		26	82	279					361	387	78	808	113
Unrealized (losses)/gains – derivative financial instruments		1	(4)	(13)					(17)	(16)	(10)	4	5
Other comprehensive income/(loss), net of tax		(2)	23	287					310	308	316	336	(599)
Total comprehensive income		614	524	629					1,153	1,767	1,931	1,231	828
Net income	(5)	(6)	(5)	(5)	(4)	$ (5)	$ (6)	$ (7)	(10)	(16)	(21)	(22)	(21)
Unrealized foreign currency translation (losses)/gains		(2)	(6)	(7)					(13)	(15)	(17)	10	13
Comprehensive income attributable to PPG		606	513	617					1,130	1,736	1,893	1,219	$ 820
As Previously Reported
Net income attributable to the controlling and noncontrolling interests	152	615	506	339	348				845	1,460	1,612	899
Unrealized foreign currency translation gains/(losses)											248	(476)
Defined benefit pension and other postretirement benefit adjustments											78	808
Unrealized (losses)/gains – derivative financial instruments											(10)	4
Other comprehensive income/(loss), net of tax											316	336
Total comprehensive income											1,928	1,235
Net income	5	6	5	5	4				10	16	(21)	(22)
Unrealized foreign currency translation (losses)/gains											(17)	10
Comprehensive income attributable to PPG											1,890	1,223
Restatement Adjustment
Net income attributable to the controlling and noncontrolling interests	4	1	(5)	3	(4)				(2)	(1)	3	(4)
Total comprehensive income											3	(4)
Net income	$ 0	$ 0	$ 0	$ 0	$ 0				$ 0	$ 0	0	0
Comprehensive income attributable to PPG											$ 3	$ (4)