Basis of Presentation	6 Months Ended
Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying Consolidated Financial Statements and footnotes thereto of Automatic Data Processing, Inc., its subsidiaries and variable interest entity (“ADP” or the “Company”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The Consolidated Financial Statements and footnotes thereto are unaudited. In the opinion of the Company’s management, the Consolidated Financial Statements reflect all adjustments, which are of a normal recurring nature, that are necessary for a fair presentation of the Company’s interim financial results. The Company has a grantor trust, which holds the majority of the funds provided by its clients pending remittance to employees of those clients, tax authorities, and other payees. The Company is the sole beneficial owner of the trust. The trust meets the criteria in Accounting Standards Codification (“ASC”) 810, “Consolidation” to be characterized as a variable interest entity (“VIE”). The Company has determined that it has a controlling financial interest in the trust because it has both (1) the power to direct the activities that most significantly impact the economic performance of the trust (including the power to make all investment decisions for the trust) and (2) the right to receive benefits that could potentially be significant to the trust (in the form of investment returns) and, therefore, consolidates the trust. Further information on these funds and the Company’s obligations to remit to its clients’ employees, tax authorities, and other payees is provided in Note 8, “Corporate Investments and Funds Held for Clients.” Restatements Effective July 1, 2018, certain prior period amounts have been restated to conform to the current period presentation in connection with the adoption of Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (ASC 606)” and ASU 2017-07, “Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Post-retirement Benefit Cost.” Also, in the first quarter of the fiscal year ended June 30, 2019 (“fiscal 2019”), the Company's chief operating decision maker (“CODM”) began reviewing segment results reported at actual interest rates and the results of the PEO segment inclusive of the results of ADP Indemnity. Additionally, the CODM reviews results with changes to certain corporate allocations. Refer to Note 2 and Note 17 for additional information. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the assets, liabilities, revenue, expenses, and accumulated other comprehensive income that are reported in the Consolidated Financial Statements and footnotes thereto. Actual results may differ from those estimates. Interim financial results are not necessarily indicative of financial results for a full year. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the Company’s Annual Report on Form 10-K for the fiscal year ended June 30, 2018 (“fiscal 2018”).

Basis of Presentation

The accompanying Consolidated Financial Statements and footnotes thereto of Automatic Data Processing, Inc., its subsidiaries and variable interest entity (“ADP” or the “Company”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The Consolidated Financial Statements and footnotes thereto are unaudited. In the opinion of the Company’s management, the Consolidated Financial Statements reflect all adjustments, which are of a normal recurring nature, that are necessary for a fair presentation of the Company’s interim financial results.

The Company has a grantor trust, which holds the majority of the funds provided by its clients pending remittance to employees of those clients, tax authorities, and other payees. The Company is the sole beneficial owner of the trust. The trust meets the criteria in Accounting Standards Codification (“ASC”) 810, “Consolidation” to be characterized as a variable interest entity (“VIE”). The Company has determined that it has a controlling financial interest in the trust because it has both (1) the power to direct the activities that most significantly impact the economic performance of the trust (including the power to make all investment decisions for the trust) and (2) the right to receive benefits that could potentially be significant to the trust (in the form of investment returns) and, therefore, consolidates the trust. Further information on these funds and the Company’s obligations to remit to its clients’ employees, tax authorities, and other payees is provided in Note 8, “Corporate Investments and Funds Held for Clients.”

Restatements

Effective July 1, 2018, certain prior period amounts have been restated to conform to the current period presentation in connection with the adoption of Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (ASC 606)” and ASU 2017-07, “Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Post-retirement Benefit Cost.” Also, in the first quarter of the fiscal year ended June 30, 2019 (“fiscal 2019”), the Company's chief operating decision maker (“CODM”) began reviewing segment results reported at actual interest rates and the results of the PEO segment inclusive of the results of ADP Indemnity. Additionally, the CODM reviews results with changes to certain corporate allocations. Refer to Note 2 and Note 17 for additional information.

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the assets, liabilities, revenue, expenses, and accumulated other comprehensive income that are reported in the Consolidated Financial Statements and footnotes thereto. Actual results may differ from those estimates. Interim financial results are not necessarily indicative of financial results for a full year. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the Company’s Annual Report on Form 10-K for the fiscal year ended June 30, 2018 (“fiscal 2018”).