Revenue (Deferred Costs) (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2018		Dec. 31, 2017	Jun. 30, 2018
Capitalized Contract Cost [Line Items]
Deferred contract costs	$ 2,338.0	[1]		$ 2,338.0	[1]		$ 2,377.4
Amortization of deferred contract costs	217.7		$ 207.6	434.6		$ 412.3
Deferred costs to obtain a contract
Capitalized Contract Cost [Line Items]
Deferred contract costs	898.1			898.1
Deferred costs to fulfill a contract
Capitalized Contract Cost [Line Items]
Deferred contract costs	$ 1,439.9			$ 1,439.9

[1] (1) The amount of total deferred costs amortized during the three and six months ended December 31, 2018 and December 31, 2017, were $217.7 million and $207.6 million, and $434.6 million and $412.3 million, respectively.