Statements of Consolidated Earnings (Parenthetical) (Unaudited) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Direct pass-through costs PEO revenues	$ 10,176.2	$ 9,207.2	$ 29,547.0	$ 26,040.3

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