Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Jan. 31, 2022	Jun. 30, 2021
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2021
Entity File Number	1-1687
Entity Registrant Name	PPG INDUSTRIES, INC.
Entity Incorporation, State or Country Code	PA
Entity Tax Identification Number	25-0730780
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 Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 40,246
Entity Common Stock, Shares Outstanding		235,998,952
Documents Incorporated by Reference	R
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Central Index Key	0000079879
Current Fiscal Year End Date	--12-31
Common Stock – Par Value $1.66 2/3
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 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