Quarterly Financial Information - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Continuing operations	$ (148.0)	$ (393.0)	$ (497.0)	$ (331.0)	$ (87.0)	$ 211.0	$ (339.0)	$ (328.0)	$ (828.0)		$ (1,221.0)		$ (1,369.0)	$ (543.0)	$ (1,311.0)
Net Income (attributable to PPG) (in dollars per share)	$ 0.59	$ 2.36	$ 1.92	$ 1.30	$ 1.29	$ (0.69)	$ 1.37	$ 1.29	$ 3.21		$ 5.58		$ 6.18	$ 3.27	$ 5.14
Continuing operations (in dollars per share)	$ (0.58)	$ (1.52)	$ (1.92)	$ (1.28)	$ (0.33)	$ 0.79	$ (1.25)	$ (1.22)	$ (3.19)		$ (4.72)		$ (5.31)	$ (2.04)	$ (4.79)
Discontinued operations	$ 3.0	$ 217.0	$ (1.0)	$ 6.0	$ 253.0	$ 27.0	$ 31.0	$ 19.0	$ 5.0		$ 222.0		$ 225.0	$ 330.0	$ 95.0
Earned payout if the target performance is achieved				150.00%	100.00%	150.00%
Stock-based compensation expense			$ 8.0	$ 9.0			$ 16.0	$ 10.0	$ 17.0	$ 26.0	$ 26.0		$ 35.0	$ 45.0	$ 54.0
Discontinued operations (in dollars per share)	$ 0.01	$ 0.84	$ 0.00	$ 0.02	$ 0.96	$ 0.10	$ 0.12	$ 0.07	$ 0.02		$ 0.86		$ 0.87	$ 1.23	$ 0.35
Income before income taxes	$ 377.0	$ 523.0	$ 659.0	$ 446.0	$ 131.0	$ (426.0)	$ 630.0	$ 444.0	$ 1,105.0	$ 1,074.0	$ 1,628.0	$ 648.0	$ 2,005.0	$ 779.0	$ 1,745.0
Environmental remediation charge													0.0	82.0	0.0
Defined benefit pension expense				18.0					34.0		52.0		65.0	85.0	$ 88.0
Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Continuing operations	$ (1.0)	$ (1.0)	$ 7.0	$ (3.0)	$ 4.0				$ 4.0		$ 3.0		$ 2.0	$ 4.0
Net Income (attributable to PPG) (in dollars per share)	$ 0.01	$ 0.00	$ (0.02)	$ 0.01	$ (0.01)				$ (0.01)		$ 0.00		$ 0.01	$ (0.01)
Continuing operations (in dollars per share)	$ (0.00)	$ (0.00)	$ 0.03	$ (0.01)	$ 0.01				$ 0.02		$ 0.01		$ 0.01	$ 0.01
Discontinued operations	$ 3.0	$ 0.0	$ 2.0	$ 0.0	$ 0.0				$ 2.0		$ 2.0		$ 5.0	$ 0.0
Stock-based compensation expense					$ 6.8
Discontinued operations (in dollars per share)	$ 0.01	$ 0.00	$ 0.01	$ 0.00	$ 0.00				$ 0.01		$ 0.01		$ 0.02	$ 0.00
Customer refundable fees, revenue recognized			$ 1.4	$ 0.4
Income before income taxes	$ 1.0	$ 2.0	(12.0)	6.0	$ (7.0)				$ (6.0)		$ (4.0)		$ (3.0)	$ (7.0)
Restructuring reserve, accrual adjustment					3.4									3.4
Accrued vacation	2.2	(1.3)	(0.9)						$ (0.9)		$ (1.3)		2.2
Severance costs	2.1	1.4	3.5
Health care expenses		3.5	3.5
Environmental remediation charge				0.5									0.5
Defined benefit pension expense	1.0	$ 1.0
Discontinued Operations | Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Discontinued operations	2.9		1.5
Income before income taxes	$ (4.7)		$ (2.5)
Share-based Compensation | Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income before income taxes				(6.8)	$ (6.8)									$ (6.8)
Other Expense
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Environmental remediation charge				$ 0.5									$ 0.5