Income Taxes (Components of Deferred Income Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Net of Valuation Allowance, Current		$ 0.0
Deferred Tax Liabilities, Net, Current		0.0
Accrued expenses not currently deductible	$ 294.5	262.8
Stock-based compensation expense	75.5	74.6
Foreign Tax Credits	49.5	47.1
Net operating losses	49.5	46.0
Other	18.7	23.7
Deferred Tax Assets, Gross	487.7	454.2
Valuation Allowance	(9.4)	(15.4)
Deferred Tax Assets, Net of Valuation Allowance	478.3	438.8
Prepaid retirement benefits	125.1	77.2
Deferred Revenue	35.5	43.2
Fixed and intangible assets	226.3	171.4
Prepaid expenses	122.5	118.0
Unrealized investment gains, net	33.4	176.2
Other	5.2	3.6
Deferred Tax Liabilities	548.0	589.6
Deferred Tax Liabilities, Net	$ 69.7	$ 150.8
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Expiration Date	Jun. 30, 2025
Net operating losses	$ 71.7
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Expiration Date	Jun. 30, 2031