Consolidated Statement of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales	$ 15,374	$ 14,748	$ 14,270
Cost of sales, exclusive of depreciation and amortization	9,001	8,209	7,665
Selling, general and administrative	3,573	3,554	3,555
Depreciation	354	331	319
Amortization	143	129	121
Research and development, net	441	451	453
Interest expense	118	105	125
Interest income	(23)	(20)	(26)
Business restructuring, net	66	0	191
Pension settlement charges	0	60	968
Asbestos settlement, net	0	0	5
Other charges	122	74	242
Other income	(114)	(150)	(127)
Income before income taxes	1,693	2,005	779
Income tax expense	353	615	214
Income from continuing operations	1,340	1,390	565
Income from discontinued operations, net of tax	18	225	330
Net income attributable to the controlling and noncontrolling interests	1,358	1,615	895
Less: net income attributable to noncontrolling interests	17	21	22
Net income (attributable to PPG)	1,341	1,594	873
Continuing operations	1,323	1,369	543
Discontinued operations	$ 18	$ 225	$ 330
Earnings per common share
Continuing operations (in dollars per share)	$ 5.43	$ 5.34	$ 2.05
Discontinued operations (in dollars per share)	0.07	0.88	1.24
Net Income (attributable to PPG) (in dollars per share)	5.50	6.22	3.29
Earnings per common share - assuming dilution
Continuing operations (in dollars per share)	5.40	5.31	2.04
Discontinued operations (in dollars per share)	0.07	0.87	1.23
Net Income (attributable to PPG) (in dollars per share)	$ 5.47	$ 6.18	$ 3.27