Derivative Instruments And Hedging Activities (Fair Value Of Derivative Contracts Designated And Not Designated As Hedging Instruments) (Details) - USD ($) $ in Millions		Feb. 28, 2016	May. 31, 2015
Derivative [Line Items]
Derivative contracts, derivative assets, fair value		$ 4.2	$ 5.3
Derivative contracts, derivative liabilities, fair value		0.0	0.0
Designated as Hedging Instruments
Derivative [Line Items]
Derivative contracts, derivative assets, fair value		1.4	4.0
Derivative contracts, derivative liabilities, fair value		0.0	0.0
Designated as Hedging Instruments | Equity forwards
Derivative [Line Items]
Derivative contracts, derivative assets, fair value	[1]	1.4	0.4
Derivative contracts, derivative liabilities, fair value	[1]	0.0	0.0
Designated as Hedging Instruments | Interest rate related
Derivative [Line Items]
Derivative contracts, derivative assets, fair value	[1]	0.0	3.6
Derivative contracts, derivative liabilities, fair value	[1]	0.0	0.0
Not Designated as Hedging Instruments
Derivative [Line Items]
Derivative contracts, derivative assets, fair value		2.8	1.3
Derivative contracts, derivative liabilities, fair value		0.0	0.0
Not Designated as Hedging Instruments | Equity forwards
Derivative [Line Items]
Derivative contracts, derivative assets, fair value	[1]	2.8	1.3
Derivative contracts, derivative liabilities, fair value	[1]	$ 0.0	$ 0.0

[1] Derivative assets and liabilities are included in receivables, net, prepaid expenses and other current assets and other current liabilities, as applicable, on our consolidated balance sheets.