Quarterly Financial Information - Quarterly Condensed Consolidated Balance Sheet (unaudited) - Summary of Restatement (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
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred tax assets, net of valuation allowance	$ 803				$ 1,110
Other	353	$ 350	$ 390	$ 439	320
Total current assets	6,477	7,638	7,141	6,763	6,574
Other assets	677	585	582	587	669
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
Accrued pensions	729	759	748	712	740
Other liabilities	967	928	910	934	935
Liabilities	10,866	11,611	11,245	10,868	10,856
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
Stockholders' equity, including portion attributable to noncontrolling interest	5,672	6,005	5,728	5,286	4,915	$ 5,069	$ 5,265
Liabilities and Equity	16,538	17,616	16,973	$ 16,154	15,771
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred tax assets, net of valuation allowance		421			184
Other			394
Total current assets			7,145
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
Accrued pensions		758
Other liabilities		928	910
Liabilities	10,865	11,605	11,242
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
Stockholders' equity, including portion attributable to noncontrolling interest	5,673	6,010	5,735		4,913
Liabilities and Equity	16,538	17,615	16,977		15,769
Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred tax assets, net of valuation allowance		1			2
Other			(4)
Total current assets			(4)
Assets		1	(4)		2
Accounts payable and accrued liabilities	1	5	3
Total current liabilities	1	5	3
Accrued pensions		1
Other liabilities		0	0
Liabilities	1	6	3
Retained earnings	(1)	(5)	(7)		(4)
Total PPG shareholders’ equity	(1)	(5)	(7)		2
Noncontrolling interests	0
Stockholders' equity, including portion attributable to noncontrolling interest	(1)	(5)	(7)
Liabilities and Equity	$ 0	$ 1	$ (4)		$ 2