Derivative Financial Instruments - Remaining Contract Maturity of Fair Value of OTC Derivative Assets and Liabilities (Footnote) (Detail) $ in Millions	Aug. 31, 2015 USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Exchange traded derivative assets	$ 144.2
Cash collateral received	208.3
Exchange traded derivative liabilities, with fair value	25.6
Cash collateral pledged	$ 317.8