Earnings per Share - Components of Basic and Diluted Earnings Per Share (Details) (USD $)
In Millions, except Per Share data, unless otherwise specified
3 Months Ended 9 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2015
Mar. 31, 2014
Weighted-average shares outstanding:        
Net earnings attributable to CDK $ 56.3 $ 69.6 $ 137.7 $ 176.0
Basic (shares) 160.6 160.6 160.7 160.6
Effect of employee stock options (shares) 0.7 0 0.4 0
Effect of employee restricted stock (shares) 0.6 0 0.4 0
Diluted (shares) 161.9 160.6 161.5 160.6
Basic earnings per share (usd per share) $ 0.35 $ 0.43 $ 0.86 $ 1.10
Diluted earnings per share (usd per share) $ 0.35 $ 0.43 $ 0.85 $ 1.10