Summary of Restricted Stock Activity (Detail) (USD $)	9 Months Ended
	May 31, 2012
Number of non-vested shares
Shares, non-vested beginning balance	14,097,278
Shares granted	5,219,122	[1]
Shares vested	(5,593,169)
Shares forfeited	(381,359)
Shares, non-vested ending balance	13,341,872
Weighted-Average Grant-Date Fair Value
Weighted-Average Grant-Date Fair Value, beginning balance	$ 12.91
Weighted-Average Grant-Date Fair Value, Shares granted	$ 19.42	[1]
Weighted-Average Grant-Date Fair Value, Shares vested	$ 10.00
Weighted-Average Grant-Date Fair Value, Shares forfeited	$ 15.56
Weighted-Average Grant-Date Fair Value, ending balance	$ 16.60

[1] For those shares granted that are based on the achievement of certain performance criteria, represents the maximum number of shares that can vest.