Cover page - shares	3 Months Ended
	Sep. 30, 2020	Oct. 27, 2020
Cover [Abstract]
Title of 12(b) Security	Common Stock, $0.10 Par Value(voting)
Document Transition Report	false
Document Quarterly Report	true
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	22-1467904
Entity Address, Address Line One	One ADP Boulevard
Entity Address, City or Town	Roseland,
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Entity File Number	1-5397
Entity Registrant Name	AUTOMATIC DATA PROCESSING, INC.
City Area Code	973
Local Phone Number	974-5000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Central Index Key	0000008670
Current Fiscal Year End Date	--06-30
Entity Filer Category	Large Accelerated Filer
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Entity Common Stock, Shares Outstanding		428,813,999
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	07068
Trading Symbol	ADP
Security Exchange Name	NASDAQ
Entity Small Business	false
Entity Emerging Growth Company	false