Statements of Consolidated Earnings (Parenthetical) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023
Income Statement [Abstract]
Direct pass-through costs PEO revenues	$ 19,420.8	$ 18,379.2	$ 36,614.4	$ 34,373.8

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