Statements Of Consolidated Earnings (Parenthetical) - USD ($) $ in Millions	12 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Direct pass-through costs, Professional Employer Organization revenues	$ 45,826.1	$ 42,688.8	$ 39,140.9

Direct pass-through costs associated with PEO, primarily consisting of payroll wages and payroll taxes.

No definition available.

Name:	adp_DirectPassThroughCostsPEORevenues
Namespace Prefix:	adp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration