Statements Of Consolidated Earnings (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011
Statements Of Consolidated Earnings [Abstract]
Direct pass-through costs, Professional Employer Organization revenues	$ 4,586.0	$ 4,177.9	$ 13,331.7	$ 11,760.6

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