Divestiture Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				6 Months Ended		12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of business	$ 29.1
Common stock, par value (usd per share)		$ 0.10			$ 0.10		$ 0.10
Dividend received from Disposal Entity					$ 0.0	$ 825.0
Gain (Loss) from Disposal Entity			$ 0.0		$ (1.4)	$ 0.0	$ 100.9
Separation Costs, Incurred Cost			$ 2.5	$ 45.3
AdvancedMD [Domain]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Date	Sep. 01, 2015
Procure-to-Pay Solutions [Domain]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Date		Jun. 26, 2015
Dealer [Domain]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Date				Sep. 30, 2014
CDK Global Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
ADP shares to be converted to Disposal Entity's Shares				1.0
Common stock, par value (usd per share)				$ 0.01
Disposal Entity's shares converted from Parent shares				3.0
Shares Distributed of Disposal Entity's common stock				160,600,000
Unvested Shares Distributed				1,000,000
Date of record for ADP stockholders to receive CDK shares				Sep. 24, 2014