Other Non-Current Assets - Schedule of Other Non-Current Assets (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Jul. 01, 2018	Jun. 30, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred client conversion and start-up costs	$ 199.4	$ 199.4		$ 169.5
Deferred sales commissions costs	85.1	85.1		0.0
Contract assets	35.9	35.9	$ 35.5	16.5
Deferred data center costs	31.9	31.9		35.0
Long-term investments	85.0	85.0		80.3
Long-term broker fees	35.4	35.4		28.7
Other	30.9	30.9		30.5
Total	503.6	503.6		$ 360.5
Amortization of deferred sales commissions and set-up costs	$ 16.8	$ 32.6