Summary of Significant Accounting Policies (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended										12 Months Ended
	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011		Sep. 30, 2011	Jun. 30, 2013 D	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2010
Property, Plant and Equipment [Line Items]
Percent of Level Two Investment Pricing Inputs Provided by Independent Pricing Service	99.00%										99.00%
Minimum days receivable considered delinquent											30
Financing Receivable, Nonaccrual Status, Minimum Number of Days Past Due											60
Number of days to resume interest revenue recognition											60
Goodwill	$ 3,052.6					$ 3,062.0					$ 3,052.6	$ 3,062.0	$ 2,980.3
Goodwill, Impairment Loss											42.7	0	0
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	227.0	[1]	482.7	352.0	302.5	256.2	450.2	372.8	[2]	300.4	1,364.1	1,379.7	1,245.0
Weighted Average Number of Shares Outstanding, Basic											482.7	487.3	493.5
Incremental Common Shares Attributable to Call Options and Warrants											3.3	3.8	3.8
Effect of Employee Restricted stock Shares On Weighted Average Number of Diluted Shares Outstanding											1.1	1.1	1.0
Weighted Average Number of Shares Outstanding, Diluted											487.1	492.2	498.3
Options excluded from the calculation of diluted earnings per share because their exercise prices exceeded the average market price											1.2	0.9	0.9
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.47		$ 1.00	$ 0.73	$ 0.63	$ 0.53	$ 0.92	$ 0.77		$ 0.62	$ 2.83	$ 2.83	$ 2.52
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.47	[1]	$ 0.99	$ 0.72	$ 0.62	$ 0.52	$ 0.91	$ 0.76	[2]	$ 0.61	$ 2.80	$ 2.80	$ 2.50
Unrecognized Tax Benefits	70.7					84.7					70.7	84.7	105.7	107.2
Tax Settlements Future Impact Potential On Earnings Maximum											15.0
Reinsurance Recoverables	1										1
Worker's Compensation per occurrence reinsurance	$ 1										$ 1
Internal Use Software Life of Asset											3 years	5 years
Internally Developed Software Amortization											3 years
Minimum [Member] | Data Processing Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life											2 years
Minimum [Member] | Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life											20 years
Minimum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life											3 years
Maximum [Member] | Data Processing Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life											5 years
Maximum [Member] | Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life											40 years
Maximum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life											7 years

[1] Net earnings from continuing operations and diluted earnings per share from continuing operations includes the impact of a goodwill impairment charge related to ADP AdvancedMD, which decreased net earnings from continuing operations by $42.7 million and diluted earnings per share from continuing operations by $0.09.

[2] Net earnings from continuing operations and diluted earnings per share from continuing operations includes the impact of a gain on sale of assets related to the rights and obligations to resell a third-party management platform which increased net earnings from continuing operations by $41.2 million and diluted earnings per share from continuing operations by $0.08.