Earnings Per Common Share (Calculations) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Earnings Per Share [Abstract]
Income (loss) from continuing operations, net of tax	$ 219	$ (50)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	2,191	63
Earnings per common share (attributable to PPG)
Net income (attributable to PPG)	2,410	13
Weighted average common shares outstanding	146.1	152.8
Earnings per common share (attributable to PPG)	$ 16.49	$ 0.08
Income (Loss) from Continuing Operations, Per Basic Share	$ 1.50	$ (0.33)
Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share	$ 14.99	$ 0.41
Earnings per common share - assuming dilution (attributable to PPG)
Net income (attributable to PPG)	$ 2,410	$ 13
Weighted average common shares outstanding	146.1	152.8
Effect of dilutive securities:
Stock options	0.9	0.9
Other stock compensation plans	0.7	0.8
Potentially dilutive common shares	1.6	1.7
Adjusted weighted average common shares outstanding	147.7	154.5
Income (loss) from continuing operations, net of tax	$ 1.48	$ (0.32)
Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share	$ 14.83	$ 0.40
Earnings per common share - assuming dilution (attributable to PPG)	$ 16.31	$ 0.08