Receivables (Narrative) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Jun. 30, 2014
Accounts, Notes, Loans and Financing Receivable, Classified [Abstract]
Recoveries and other	$ 10.7
Proceeds from the sale of notes receivable	$ 226.7	$ 0
Percentage Of Notes Receivable Classified As Current			100.00%	100.00%
Allowance for Doubtful Accounts, Percent of Notes Receivable	2.00%			5.00%

Allowance for Doubtful Accounts, Percent of Notes Receivable

No definition available.

Name:	adp_AllowanceForDoubtfulAccountsPercentOfNotesReceivable
Namespace Prefix:	adp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of notes receivable that are classified as current

+ References

No definition available.

+ Details

Name:	adp_PercentageOfNotesReceivableClassifiedAsCurrent
Namespace Prefix:	adp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_AccountsNotesAndLoansReceivableClassifiedAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of recovery of financing receivables doubtful of collection that were previously charged off.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(4)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow associated with the sale of a borrowing supported by a written promise to pay an obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromSaleOfNotesReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration