Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net earnings	$ 24.1	$ 90.9	$ 108.2	$ 183.2
Other comprehensive income (loss):
Foreign currency translation adjustments	32.0	(12.1)	12.1	(18.1)
Total other comprehensive income (loss)	32.0	(12.1)	12.1	(18.1)
Comprehensive income	56.1	78.8	120.3	165.1
Less: comprehensive income attributable to noncontrolling interest	1.8	1.9	3.9	3.9
Comprehensive income attributable to CDK	$ 54.3	$ 76.9	$ 116.4	$ 161.2