Investments (Maturities Of Fixed Income Securities) (Detail) (USD $) In Millions, unless otherwise specified	Oct. 27, 2012
Fixed Income Securities Matures Within One Year [Member]
Schedule of Investments [Line Items]
Fixed Income Available For Sale Debt And Equity Securities Amortized Cost	$ 17,224
Financial Instruments, Owned and Not Pledged, at Fair Value	17,238
Fixed Income Securities Maturities Between One And Two Years [Member]
Schedule of Investments [Line Items]
Fixed Income Available For Sale Debt And Equity Securities Amortized Cost	10,763
Financial Instruments, Owned and Not Pledged, at Fair Value	10,798
Fixed Income Securities Maturities Between Two And Five Years [Member]
Schedule of Investments [Line Items]
Fixed Income Available For Sale Debt And Equity Securities Amortized Cost	10,265
Financial Instruments, Owned and Not Pledged, at Fair Value	10,339
Fixed Income Securities Maturities Beyond Five Years [Member]
Schedule of Investments [Line Items]
Fixed Income Available For Sale Debt And Equity Securities Amortized Cost	83
Financial Instruments, Owned and Not Pledged, at Fair Value	89
Fixed Income Securities [Member]
Schedule of Investments [Line Items]
Fixed Income Available For Sale Debt And Equity Securities Amortized Cost	38,335
Financial Instruments, Owned and Not Pledged, at Fair Value	$ 38,464