Statements Of Consolidated Earnings (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Statements Of Consolidated Earnings [Abstract]
Direct pass-through costs, Professional Employer Organization revenues	$ 4,810.4	$ 4,231.3	$ 8,745.7	$ 7,582.7

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