Condensed Consolidated Statement of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales	$ 3,817	$ 3,776	$ 11,729	$ 11,066
Cost of sales, exclusive of depreciation and amortization	2,253	2,104	6,813	6,089
Selling, general and administrative	867	894	2,718	2,645
Depreciation	89	85	267	245
Amortization	33	32	103	95
Research and development, net	110	114	336	335
Interest expense	31	27	88	78
Interest income	(6)	(5)	(18)	(13)
Pension settlement charge	0	0	0	22
Business restructuring charge	(12)	0	71	0
Other charges	25	18	72	51
Other income	(24)	(16)	(72)	(109)
Income from continuing operations before income taxes	451	523	1,351	1,628
Income tax expense	79	124	270	391
Income from continuing operations	372	399	1,081	1,237
Income from discontinued operations, net of tax	10	217	16	222
Net income attributable to controlling and noncontrolling interests	382	616	1,097	1,459
Less: Net income attributable to noncontrolling interests	4	6	14	16
Net income (attributable to PPG)	378	610	1,083	1,443
Income from continuing operations, net of tax	368	393	1,067	1,221
Income from discontinued operations, net of tax	$ 10	$ 217	$ 16	$ 222
Income from continuing operations, net of tax (in usd per share)	$ 1.52	$ 1.53	$ 4.34	$ 4.75
Income from discontinued operations, net of tax (in usd per share)	0.04	0.85	0.07	0.86
Net income (attributable to PPG) (in usd per share)	1.56	2.38	4.41	5.61
Income from continuing operations, net of tax (in usd per share)	1.51	1.52	4.32	4.72
Income from discontinued operations, net of tax (in usd per share)	0.04	0.84	0.06	0.86
Net income (attributable to PPG) (in usd per share)	1.55	2.36	4.38	5.58
Dividends per common share (in usd per share)	$ 0.48	$ 0.45	$ 1.38	$ 1.25