Accumulated Other Comprehensive Income (Loss), Net of Tax (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012		Oct. 01, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]
Market value adjustments for investments and hedges	$ 8		$ (48)
Foreign currency translation and other	48		43
Unrecognized pension and postretirement medical expense	(2,537)		(2,625)
Accumulated other comprehensive income (loss)	$ (2,481)	[1]	$ (2,630)	[1]

[1] Accumulated other comprehensive income (loss) and components of other comprehensive income (loss) are net of 37% estimated tax