Restatement of Previously Reported Consolidated Annual Financial Statements - Summary of Restatement - Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred income taxes	$ 803				$ 1,110
Deferred income taxes	305	$ 422	$ 321	$ 170	186
Total Assets	16,538	17,616	16,973	16,154	15,771
Accounts payable and accrued liabilities	3,781	3,900	3,656	3,517	3,460
Total current liabilities	3,895	4,623	4,444	4,285	4,253
Total liabilities	10,866	11,611	11,245	10,868	10,856
Additional paid-in capital	756	745	723	711	707
Retained earnings	17,140	17,101	16,606	16,214	15,980
Total PPG shareholders’ equity	5,557	5,897	5,623	5,192	4,828
Noncontrolling interests	115	108	105	94	87
Total shareholders’ equity	5,672	6,005	5,728	5,286	4,915	$ 5,069	$ 5,265
Total	16,538	17,616	16,973	$ 16,154	15,771
As Previously Reported
Deferred income taxes		421			184
Total Assets		17,615	16,977		15,769
Accounts payable and accrued liabilities	3,780	3,895	3,653
Total current liabilities	3,894	4,618	4,441
Total liabilities	10,865	11,605	11,242
Additional paid-in capital					701
Retained earnings	17,141	17,106	16,613		15,984
Total PPG shareholders’ equity	5,558	5,902	5,630		4,826
Noncontrolling interests	115	108	105		87
Total shareholders’ equity	5,673	6,010	5,735		4,913
Total	16,538	17,615	16,977		15,769
Restatement Adjustment
Deferred income taxes		1			2
Total Assets		1	(4)		2
Accounts payable and accrued liabilities	1	5	3
Total current liabilities	1	5	3
Total liabilities	1	6	3
Additional paid-in capital					6
Retained earnings	(1)	(5)	(7)		(4)
Total PPG shareholders’ equity	(1)	(5)	(7)		2
Noncontrolling interests	0
Total shareholders’ equity	(1)	(5)	(7)
Total	$ 0	$ 1	$ (4)		$ 2