Financial Instruments, Hedging Activities and Fair Value Measurements (Additional Information) (Detail) € in Millions, $ 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
Interest Paid by PPG to Counter Party			10
Forward Contract Indexed To Issuers Equity Fair Value						$ 258
Foreign Currency Contracts, Liability, Fair Value Disclosure			2
Derivative Instruments in Hedges, Net Investment in Foreign Operations, Assets, Fair Value, Net	$ (2)		(65)
Notional Amount of Nonderivative Instruments | €		€ 300
Fair Value of Debt Instrument Designated as a Hedge of Net Investment in Foreign Operations	2,700		2,900
Derivative, Cash Received on Hedge	3		0		$ 19
Foreign Currency Contracts, Liability, Fair Value Disclosure	20
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	16		482
Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Foreign Currency Contracts, Liability, Fair Value Disclosure	3		$ 13
Net Investment Hedging
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional Amount of Nonderivative Instruments | €		€ 2,300		€ 2,800
Designated as Hedging Instrument [Member] | 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