Consolidated Statement of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Net sales	$ 13,834	$ 15,146	$ 15,374
Cost of sales, exclusive of depreciation and amortization	7,777	8,653	9,001
Selling, general and administrative	3,389	3,604	3,573
Depreciation	371	375	354
Amortization	138	136	143
Research and development, net	379	432	441
Interest expense	138	132	118
Interest income	(23)	(32)	(23)
Impairment charges	93	0	0
Business restructuring	174	176	66
Other charges	104	98	122
Other income	(68)	(89)	(114)
Income before income taxes	1,362	1,661	1,693
Income tax expense	291	392	353
Income from continuing operations	1,071	1,269	1,340
Income from discontinued operations, net of tax	3	0	18
Net income attributable to the controlling and noncontrolling interests	1,074	1,269	1,358
Less: Net income attributable to noncontrolling interests	15	26	17
Net income (attributable to PPG)	1,059	1,243	1,341
Income from continuing operations, net of tax	1,056	1,243	1,323
Income from discontinued operations, net of tax	$ 3	$ 0	$ 18
Earnings per common share
Continuing operations (in dollars per share)	$ 4.46	$ 5.25	$ 5.43
Discontinued operations (in dollars per share)	0.01	0	0.07
Net Income (attributable to PPG) (in dollars per share)	4.47	5.25	5.50
Earnings per common share - assuming dilution
Continuing operations (in dollars per share)	4.44	5.22	5.40
Discontinued operations (in dollars per share)	0.01	0	0.07
Net Income (attributable to PPG) (in dollars per share)	$ 4.45	$ 5.22	$ 5.47