Share-Based Awards and Options (Tables)

12 Months Ended

May 31, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Compensation Cost for Share-based Payment Arrangements [Table Text Block]

The following table summarizes the share-based compensation cost charged to income for (i) all stock options granted, (ii) our restricted stock program (including PRSUs and TSRs), and (iii) our employee stock purchase plan. The total income tax benefit recognized for share-based compensation in the accompanying statements of income is also presented.

	2012			2011			2010
Share-based compensation cost	$	16.4		$	15.9		$	18.1
Income tax benefit	$	(6.0	)	$	(5.5	)	$	(6.3	)

Schedule of Stock Option Plan Activity [Table Text Block]

The following is a summary of our stock option activity as of and for the years ended May 31, 2012 and 2011:

					Weighted
			Weighted		Average
			Average		Remaining	Aggregate
			Exercise		Contractual	Intrinsic
	Options		Price		Term	Value
	(in thousands)				(years)	(in millions)
Outstanding at May 31, 2010	3,042		$	31	4.9	32.7
Granted	325		38
Forfeited	(200	)	36
Exercised	(714	)	29
Outstanding at May 31, 2011	2,453		32		5.1	45.9
Granted	—		—
Forfeited	(51	)	28
Exercised	(254	)	32
Outstanding at May 31, 2012	2,148		34		4.1	20.7
Options vested and exercisable at May 31, 2012	1,770		$	32	3.4	19.7
Options vested and exercisable at May 31, 2011	1,821		$	31	4.0	38.5

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value [Table Text Block]

The weighted average grant-date fair values of each option granted in fiscal 2012, 2011, and 2010 under each plan are as follows:

	2012		2011		2010
2005 Plan	$	—	$	11	$	14
Director Plan	$	—	$	12	$	15

Schedule of Stock Options Valuation Assumptions [Table Text Block]

The fair value of each option granted was estimated on the date of grant using the Black-Scholes valuation model with the following weighted average assumptions for grants during the period:

	2012	2011	2010
2005 Plan:
Risk-free interest rates	—	1.74%	2.72%
Expected volatility	—	31.96%	32.31%
Dividend yields	—	0.21%	0.21%
Expected lives	—	5 years	5 years
Director Plan:
Risk-free interest rates	—	1.31%	2.24%
Expected volatility	—	31.96%	32.31%
Dividend yields	—	0.21%	0.21%
Expected lives	—	5 years	5 years

Schedule of Changes in Non-Vested Restricted Stock Awards Activity [Table Text Block]

The following table summarizes the changes in non-vested restricted stock awards for the years ended May 31, 2012 and 2011(share awards in thousands):

	Shares		Weighted Average Grant-Date Fair Value
Non-vested at May 31, 2010	713		$	42
Granted	461		38
Vested	(259	)	42
Forfeited	(46	)	40
Non-vested at May 31, 2011	869		40
Granted	472		48
Vested	(321	)	40
Forfeited	(79	)	43
Non-vested at May 31, 2012	941		44