Earnings Per Common Share (Calculations) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share [Abstract]
Income from continuing operations, net of tax	$ 341	$ 297	$ 560	$ 247
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	65	2,191	128
Earnings per common share (attributable to PPG)
Net income (attributable to PPG)	341	362	2,751	375
Weighted average common shares outstanding	143.4	153.2	145.0	153.0
Earnings per common share (attributable to PPG)	$ 2.38	$ 2.37	$ 18.97	$ 2.45
Income (Loss) from Continuing Operations, Per Basic Share	$ 2.38	$ 1.94	$ 3.86	$ 1.61
Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share	$ 0.00	$ 0.43	$ 15.11	$ 0.84
Earnings per common share - assuming dilution (attributable to PPG)
Net income (attributable to PPG)	$ 341	$ 362	$ 2,751	$ 375
Weighted average common shares outstanding	143.4	153.2	145.0	153.0
Effect of dilutive securities:
Stock options	0.9	0.9	0.9	0.9
Other stock compensation plans	0.7	0.9	0.8	0.8
Potentially dilutive common shares	1.6	1.8	1.7	1.7
Adjusted weighted average common shares outstanding	145.0	155.0	146.7	154.7
Income from continuing operations, net of tax	$ 2.35	$ 1.92	$ 3.82	$ 1.60
Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share	$ 0.00	$ 0.42	$ 14.94	$ 0.82
Earnings per common share - assuming dilution (attributable to PPG)	$ 2.35	$ 2.34	$ 18.76	$ 2.42