Stock-Based Compensation (Additional Information) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended	9 Months Ended				12 Months Ended		9 Months Ended	12 Months Ended		9 Months Ended	12 Months Ended			9 Months Ended	12 Months Ended			9 Months Ended	12 Months Ended		9 Months Ended	12 Months Ended		9 Months Ended	12 Months Ended		9 Months Ended	12 Months Ended				9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 OptionPlan	Sep. 30, 2011	Dec. 31, 2011	Sep. 30, 2012 Stock Options [Member]	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2011 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member] Minimum [Member]	Dec. 31, 2011 Restricted Stock Units (RSUs) [Member] Minimum [Member]	Dec. 31, 2010 Restricted Stock Units (RSUs) [Member] Minimum [Member]	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member] Maximum [Member]	Dec. 31, 2011 Restricted Stock Units (RSUs) [Member] Maximum [Member]	Dec. 31, 2010 Restricted Stock Units (RSUs) [Member] Maximum [Member]	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member] 2010-2013 Performance Period [Member]	Dec. 31, 2011 Restricted Stock Units (RSUs) [Member] 2010-2013 Performance Period [Member]	Dec. 31, 2010 Restricted Stock Units (RSUs) [Member] 2010-2013 Performance Period [Member]	Dec. 31, 2011 Restricted Stock Units (RSUs) [Member] 2010-2013 Performance Period [Member] Performance Targets Met [Member]	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member] Performance Period 2011 to 2013 [Member]	Dec. 31, 2011 Restricted Stock Units (RSUs) [Member] Performance Period 2011 to 2013 [Member]	Dec. 31, 2010 Restricted Stock Units (RSUs) [Member] Performance Period 2011 to 2013 [Member]	Dec. 31, 2011 Restricted Stock Units (RSUs) [Member] Performance Period 2011 to 2013 [Member] Performance Targets Met [Member]	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member] 2012-2014 Performance Period [Member]	Dec. 31, 2011 Restricted Stock Units (RSUs) [Member] 2012-2014 Performance Period [Member]	Dec. 31, 2010 Restricted Stock Units (RSUs) [Member] 2012-2014 Performance Period [Member]	Sep. 30, 2012 Executive Officer Incentive Plan [Member]	Dec. 31, 2011 Executive Officer Incentive Plan [Member]	Dec. 31, 2010 Executive Officer Incentive Plan [Member]	Sep. 30, 2012 Executive Officer Incentive Plan [Member] Minimum [Member]	Dec. 31, 2011 Executive Officer Incentive Plan [Member] Minimum [Member]	Dec. 31, 2010 Executive Officer Incentive Plan [Member] Minimum [Member]	Sep. 30, 2012 Executive Officer Incentive Plan [Member] Maximum [Member]	Dec. 31, 2011 Executive Officer Incentive Plan [Member] Maximum [Member]	Dec. 31, 2010 Executive Officer Incentive Plan [Member] Maximum [Member]	Dec. 31, 2010 Executive Officer Incentive Plan [Member] 2010-2013 Performance Period [Member]	Dec. 31, 2011 Executive Officer Incentive Plan [Member] Performance Period 2011 to 2013 [Member]	Sep. 30, 2012 Executive Officer Incentive Plan [Member] 2012-2014 Performance Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants under the PPG Omnibus Plan	8,400,000		8,400,000
Total stock-based compensation cost	$ 21	$ 6	$ 53	$ 27
Total income tax benefit recognized related to the stock-based compensation	$ 7	$ 2	$ 18	$ 9
Description of the terms of the outstanding stock options for the PPG Omnibus Plan and the PPG Stock Plan for certain employees			The options are generally exercisable beginning from six to 48 months after being granted and have a maximum term of 10 years.
Maximum term of the outstanding stock options for the PPG Omnibus Plan and the PPG Stock Plan for certain employees			10 years
Number of stock option plans			2
Options exercisable period, minimum	6 months		6 months
Options exercisable period, maximum	48 months		48 months
Stock options granted from the PPG Omnibus Plan			792,957	628,927
Stock options granted from the PPG Omnibus Plan, weighted average exercise price per share			$ 90.19	$ 88.29
Stock options granted from the PPG Omnibus Plan, weighted average fair value per share			$ 17.97	$ 19.00
Award vest period (in years)						3 years	3 years																			3 years	3 years	3 years
Percentage of the target award that is paid based on performance									0.00%	0.00%	0.00%	180.00%	180.00%	180.00%															0.00%	0.00%	0.00%	220.00%	220.00%	220.00%
Percentage of the target award that is assumed to vest for the purposes of expense recognition															180.00%	150.00%	150.00%		100.00%	100.00%	100.00%		100.00%	100.00%	100.00%
Number of performance targets					4,000,000											4		4		2		2
RSUs granted							248,732	221,009
RSUs granted, weighted average fair value per share							$ 84.31	$ 87.53
Earned payout if the target performance is achieved																										100.00%
Performance share payout description																																			Dividend equivalents for the award period, which will be paid to participants with the award payout at the end of the period based on the actual number of contingent shares that are earned.	Dividend equivalents for the award period, which will be paid to participants with the award payout at the end of the period based on the actual number of contingent shares that are earned.	Dividend equivalents for the award period, which will be paid to participants with the award payout at the end of the period based on the actual number of contingent shares that are earned.