Cover	6 Months Ended
	Jun. 30, 2021 shares
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	1-1687
Entity Registrant Name	PPG INDUSTRIES INC
Entity Tax Identification Number	25-0730780
Entity Incorporation, State or Country Code	PA
Entity Address, Address Line One	One PPG Place
Entity Address, City or Town	Pittsburgh
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	15272
City Area Code	412
Local Phone Number	434-3131
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	237,356,580
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Central Index Key	0000079879
Current Fiscal Year End Date	--12-31
Common Stock
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, par value $1.66 2/3
Trading Symbol	PPG
Security Exchange Name	NYSE
0.875% Notes Due 2022
Entity Information [Line Items]
Title of 12(b) Security	0.875% Notes due 2022
Trading Symbol	PPG 22
Security Exchange Name	NYSE
0.875% Notes Due 2025
Entity Information [Line Items]
Title of 12(b) Security	0.875% Notes due 2025
Trading Symbol	PPG 25
Security Exchange Name	NYSE
1.400% Notes Due 2027
Entity Information [Line Items]
Title of 12(b) Security	1.400% Notes due 2027
Trading Symbol	PPG 27
Security Exchange Name	NYSE