Assets and Liabilities Measured at Fair Value on Recurring Basis (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Oct. 01, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of derivative contracts in liability position netted against contracts in asset position	$ 122	$ 167