Employee Benefit Plans (Additional Information) (Detail) $ in Millions		1 Months Ended	2 Months Ended	3 Months Ended		9 Months Ended	12 Months Ended
	Oct. 01, 2016 USD ($)	Aug. 31, 2016 USD ($) purchase_agreement insurance_company retiree	Sep. 30, 2016 USD ($) plan	Dec. 31, 2016 USD ($)	Jun. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jul. 31, 2016
Pension and Other Postretirement Benefits Disclosure [Line Items]
Noncash Pension Settlement Charge - before tax									$ 968.0	$ 0.0	$ 0.0
Discount rate used to calculate benefit obligation				3.70%					3.70%	4.10%
Defined benefit pension expense									$ 86.0	$ 91.0	$ 58.0
ABO for all defined benefit pension plans				$ 3,171.0					3,171.0	$ 5,220.0
Net actuarial loss arising during the year									$ 277.0
Return on plan assets assumption									6.10%	6.10%	6.50%
Impact on net periodic pension expense									$ 11.0
Weighted-average healthcare cost trend rate assumed for next fiscal year									6.10%
Assumed ultimate health care cost trend rate									4.40%
Assumed year that ultimate health care cost trend rate will be reached				2024					2024
Benefits paid										$ 13.0
Accrued pensions				$ 740.0					$ 740.0	695.0
Defined contribution plan contribution rates as percentage of employee earnings									6.00%
Company-matching contribution, percent of match									100.00%
Compensation expense related to the ESOP									$ 48.0	44.0	$ 42.0
Deductible dividends on PPG shares held by the ESOP									14.0	13.0	14.0
Expense (income) of the deferred compensation plan									7.0	5.0	10.0
Increase (Decrease) in fair value of investments									5.0	3.0	8.0
Realized gains on the investment portfolio of the deferred compensation plan									3.0	3.0	3.0
Obligations under the deferred compensation plan										124.0
Investments in marketable securities by the deferred compensation plan				82.0					82.0	81.0
Aggregate PBO for the pension plans with PBO in excess of plan assets				2,406.0					2,406.0	4,717.0
Aggregate fair value of plan assets for the pension plans with PBO in excess of plan assets				1,609.0					1,609.0	3,937.0
Aggregate ABO for the pension plans with ABO in excess of plan assets				2,302.0					2,302.0	4,351.0
Fair value of plan assets for the pension plans with ABO in excess of plan assets				1,575.0					1,575.0	3,676.0
Estimated future benefit payments in 2018				61.0					61.0
Estimated future benefit payments in 2019				60.0					60.0
Estimated future benefit payments in 2020				60.0					60.0
Estimated future benefit payments in 2021				59.0					59.0
Pensions
Pension and Other Postretirement Benefits Disclosure [Line Items]
Recognized expense for defined contribution pension plans									70.0	60.0	55.0
Accrued pensions				11.0					11.0	12.0
Pittsburgh Glass Works LLC
Pension and Other Postretirement Benefits Disclosure [Line Items]
Liabilities for pension and post-employment benefits earned for service up to the time of sale				342.0					342.0	867.0
Costs related to the pension and other postemployment benefit liabilities of the divested business									$ 20.0	17.0	19.0
Minimum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Company-matching contribution									2.00%
Maximum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Company-matching contribution									5.00%
United States Pension Plans of US Entity, Defined Benefit
Pension and Other Postretirement Benefits Disclosure [Line Items]
Number of Definitive Purchase Agreements | purchase_agreement		2
Number of insurance companies to service future benefit obligations | insurance_company		2
Number of Company's retirees affected by annuity purchase | retiree		13,200
Increase (decrease) in benefit obligation due to settlements				(1,600.0)					$ (1,600.0)
Noncash Pension Settlement Charge - after tax									535.0
Noncash Pension Settlement Charge - before tax									857.0
Contributions to defined benefit pension plans									146.0	$ 234.0	2.0
Discount rate used to calculate benefit obligation										4.50%		3.60%
Increase (decrease) in benefit obligation due to U.S. Plan Merger and Remeasurement				306.0					306.0
Increase (decrease) in pension expense				10.0					$ 10.0
Return on plan assets assumption									7.15%
Foreign Pension Plan
Pension and Other Postretirement Benefits Disclosure [Line Items]
Noncash Pension Settlement Charge - after tax									$ 47.0
Noncash Pension Settlement Charge - before tax									64.0
Contributions to defined benefit pension plans			$ 1.0						58.0	$ 39.0	39.0
Increase (decrease) in benefit obligation due to U.S. Plan Merger and Remeasurement				(200.0)					(200.0)
Estimated future mandatory contributions, low end of range				20.0					20.0
Estimated future mandatory contributions, high end of range				30.0					30.0
Number of legacy plan windups | plan			2
After-tax wind-up charges			$ (34.0)
Pre-tax gain (loss) due to settlements			$ (47.0)			$ (7.0)
Foreign Pension Plan | Canada
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contributions to defined benefit pension plans									7.0
Pensions
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contributions to defined benefit pension plans									204.0	273.0
Pension assets transferred									(3.0)	0.0
Plan settlements									2,338.0	17.0
Net actuarial loss arising during the year									260.0
Estimated amounts of accumulated net actuarial loss that will be amortized from AOCI into net periodic benefit cost in 2012									77.0
Impact on net periodic pension expense									28.0
Benefits paid									233.0	271.0
Accrued pensions				740.0					740.0	695.0
Estimated future benefit payments in 2017				169.0					169.0
Estimated future benefit payments in 2018				124.0					124.0
Estimated future benefit payments in 2019				118.0					118.0
Estimated future benefit payments in 2020				125.0					125.0
Estimated future benefit payments in 2021				127.0					127.0
Estimated aggregate future benefits payments for the five years thereafter				$ 704.0					704.0
Pensions | Pensions
Pension and Other Postretirement Benefits Disclosure [Line Items]
Estimated amounts of accumulated net actuarial loss that will be amortized from AOCI into net periodic benefit cost in 2012									$ (110.0)	(119.0)	(77.0)
Welfare Benefits - U.S. and Canada
Pension and Other Postretirement Benefits Disclosure [Line Items]
Percentage of defined benefit pension plan assets market value				88.00%					88.00%
Postretirement Health Coverage
Pension and Other Postretirement Benefits Disclosure [Line Items]
Increase (decrease) in benefit obligation due to U.S. Plan Merger and Remeasurement		$ (306.0)
Amortization reduction period		5 years 7 months 6 days
Other Postretirement Benefits
Pension and Other Postretirement Benefits Disclosure [Line Items]
Net actuarial loss arising during the year									$ 17.0
Estimated amounts of accumulated net actuarial loss that will be amortized from AOCI into net periodic benefit cost in 2012									22.0
Estimated amounts of accumulated prior service cost that will be amortized from AOCI into net periodic benefit cost in 2012									(59.0)
Impact on net periodic pension expense									24.0
Benefits paid									53.0	52.0
Accrued pensions				$ 0.0					0.0	0.0
Estimated future benefit payments in 2017				61.0					61.0
Estimated aggregate future benefits payments for the five years thereafter				267.0					267.0
U.S. Pension Settlement Charges
Pension and Other Postretirement Benefits Disclosure [Line Items]
Plan settlements					$ 41.0
Scenario, Forecast
Pension and Other Postretirement Benefits Disclosure [Line Items]
Weighted-average healthcare cost trend rate assumed for next fiscal year								6.30%
Assumed ultimate health care cost trend rate								4.50%
Scenario, Forecast | United States Pension Plans of US Entity, Defined Benefit
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contributions to defined benefit pension plans								$ 29.0
Return on plan assets assumption								7.50%
Scenario, Forecast | Foreign Pension Plan
Pension and Other Postretirement Benefits Disclosure [Line Items]
Return on plan assets assumption								5.40%
Flat Glass Business [Member]
Pension and Other Postretirement Benefits Disclosure [Line Items]
Settlement charge	$ 11.0
Defined benefit pension expense									4.0	5.0	4.0
Other postretirement benefit expense									1.0	1.0	$ 1.0
Flat Glass Business [Member] | United States Pension Plans of US Entity, Defined Benefit
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contributions to defined benefit pension plans										$ 16.0
Flat Glass Business [Member] | Pensions
Pension and Other Postretirement Benefits Disclosure [Line Items]
Increase (decrease) in benefit obligation due to settlements	(100.0)
Pension assets transferred									55.0
Flat Glass Business [Member] | Scenario, Forecast | Pensions | Minimum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Pension assets transferred							$ 5.0
Flat Glass Business [Member] | Scenario, Forecast | Pensions | Maximum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Pension assets transferred							$ 10.0
European Fiber Glass
Pension and Other Postretirement Benefits Disclosure [Line Items]
Noncash Pension Settlement Charge - before tax				$ 46.0
Settlement charge	46.0
European Fiber Glass | Pensions
Pension and Other Postretirement Benefits Disclosure [Line Items]
Increase (decrease) in benefit obligation due to settlements	$ (340.0)
Pension assets transferred									$ 250.0
United States, Canada, Netherlands and United Kingdom
Pension and Other Postretirement Benefits Disclosure [Line Items]
Percentage of defined benefit pension plan assets market value				93.00%					93.00%