Financial Instruments, Hedging Activities and Fair Value Measurements (Additional Information) (Detail) € in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2017 EUR (€)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 EUR (€)	Dec. 31, 2015 USD ($)	Jun. 30, 2016 USD ($) shares
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Forward Contract Indexed to Issuer's Equity, Indexed Shares | shares						2,777,778
Forward Contract Indexed To Issuers Equity Shares Principal Amount			$ 60,000,000
Interest Paid by PPG to Counter Party			10,000,000
Forward Contract Indexed To Issuers Equity Fair Value						$ 258,000,000
Foreign Currency Contracts, Liability, Fair Value Disclosure			2,000,000
Derivative Instruments in Hedges, Net Investment in Foreign Operations, Assets, Fair Value, Net	$ 2,000,000		65,000,000
Notional Amount of Nonderivative Instruments | €		€ 300
Fair Value of Debt Instrument Designated as a Hedge of Net Investment in Foreign Operations	2,700,000,000		2,900,000,000
Derivative, Cash Received on Hedge	3,000,000		0		$ 19,000,000
Foreign Currency Contracts, Liability, Fair Value Disclosure	20,000,000
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	16,000,000		482,000,000
Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Foreign Currency Contracts, Liability, Fair Value Disclosure	3,000,000		13,000,000
Net Investment Hedging
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Nonderivative Instruments | €		€ 2,300		€ 2,800
Designated as Hedging Instrument | Foreign Currency Contracts | Cash Flow Hedging | Settlement Date 15 March 2018
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Derivative Instruments Designated as Net Investment Hedges	$ 560,000,000		$ 560,000,000