Cover Page - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Feb. 15, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	1-5690
Entity Registrant Name	GENUINE PARTS CO
Entity Incorporation, State or Country Code	GA
Entity Tax Identification Number	58-0254510
Entity Address, Address Line One	2999 WILDWOOD PARKWAY,
Entity Address, City or Town	ATLANTA,
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30339
City Area Code	678
Local Phone Number	934-5000
Title of 12(b) Security	Common Stock, $1.00 par value per share
Trading Symbol	GPC
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
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
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Public Float			$ 12,200
Entity Common Stock, Shares Outstanding		144,404,012
Documents Incorporated by Reference	Specifically identified portions of the Company’s definitive Proxy Statement for the Annual Meeting of Shareholders to be held on April 29, 2021 are incorporated by reference into Part III of this Form 10-K.
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0000040987
Current Fiscal Year End Date	--12-31