Corporate Investments And Funds Held For Clients (Narrative) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
Mar. 31, 2013	Jun. 30, 2012
Schedule of Available-for-sale Securities [Line Items]
Client Fund Obligation repayment period	1 year
Available-for-sale securities - fair value	$ 18,986.6	$ 18,093.4
Earliest non-callable debt maturity date	April 2013
Latest non-callable debt maturity date	February 2023
Earliest corporate bond maturity date	April 2013
Latest corporate bond maturity date	December 2022
Length of shortest cash flow of residential mortgages used as collateral for companies mortgage backed securities (in years)	15 years
Length of longest cash flow of residential mortgages used as collateral for company's mortgage backed securities (in years)	30 years
Client funds obligations	29,703.4	20,856.2
Client funds investments with original maturities	90 days or less
Percentage of the available-for-sale securities were rated AAA or AA	84.00%
Federal Home Loan Banks [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	4,438.6	4,189.1
Federal Farm Credit Banks [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	1,257.1	1,134.1
Fixed Rate Credit Card [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	811.2	323.0
Asset-Backed Auto Loan Receivables [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	267.0	85.1
Rate Reduction [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	98.9	140.0
Supranational Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	434.8	427.7
Sovereign Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	421.0	405.0
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	200.4	282.3
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - fair value	$ 120.3	$ 135.3

Period of time from the Balance Sheet Date that client fund obligations has to be repaid

No definition available.

Name:	adp_ClientFundObligationRepaymentPeriod
Namespace Prefix:	adp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Client funds investments, maturity period.

+ References

No definition available.

+ Details

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- Definition

Represent the Company's contractual obligations to remit funds to satisfy clients' payroll and tax payment obligations and are recorded on the Balance Sheet at the time that the Company impounds funds from clients.

+ References

No definition available.

+ Details

Name:	adp_ClientFundsObligations
Namespace Prefix:	adp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Earliest Corporate bond debt maturity date

+ References

No definition available.

+ Details

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Namespace Prefix:	adp_
Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Earliest non-callable debt maturity date

+ References

No definition available.

+ Details

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Namespace Prefix:	adp_
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- Definition

Latest corporate debt maturity date

+ References

No definition available.

+ Details

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Namespace Prefix:	adp_
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- Definition

Latest non-callable debt maturity date

+ References

No definition available.

+ Details

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- Definition

Length of longest cash flow of residential mortgages used as collateral for the Company's mortgage-backed securities (in years).

+ References

No definition available.

+ Details

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Namespace Prefix:	adp_
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- Definition

Length of shortest cash flow of residential mortgages used as collateral for companies mortgage backed securities (in years)

+ References

No definition available.

+ Details

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- Definition

Percentage of the available-for-sale securities were rated AAA or AA

+ References

No definition available.

+ Details

Name:	adp_PercentageOfAvailableForSaleSecuritiesWereRatedAaaOrAa
Namespace Prefix:	adp_
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Period Type:	duration

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7534914&loc=d3e22054-111558

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Available-for-Sale Securities

-URI http://asc.fasb.org/extlink&oid=6505594

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