Quarterly report pursuant to Section 13 or 15(d)

Marketable Securities (Details)

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Marketable Securities (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 6 Months Ended
Mar. 31, 2013
Mar. 25, 2012
Mar. 31, 2013
Mar. 25, 2012
Sep. 30, 2012
Schedule of Marketable Securities [Line Items]          
Total marketable securities - Current $ 9,400   $ 9,400   $ 8,567
Total marketable securities - Noncurrent 17,046   17,046   14,463
Trading Securities [Abstract]          
Trading - Current 506   506   479
Trading - Noncurrent 674   674   550
Net gains (losses) recognized on debt securities classified as trading that are still held at the end of the period (15) 12 (16) 10  
Available-for-sale Securities [Abstract]          
Available-for-sale - Current 8,894   8,894   8,088
Available-for-sale - Noncurrent 15,833   15,833   13,393
Fair Value Option [Abstract]          
Effective ownership interest in debt fund (fair value option) 21.00%   21.00%    
U.S. Treasury securities and government-related securities [Member]
         
Trading Securities [Abstract]          
Trading - Current 224   224   196
Trading - Noncurrent 155   155   254
Available-for-sale Securities [Abstract]          
Available-for-sale - Current 353   353   362
Available-for-sale - Noncurrent 630   630   592
Corporate bonds and notes [Member]
         
Trading Securities [Abstract]          
Trading - Current 282   282   283
Trading - Noncurrent 321   321   176
Available-for-sale Securities [Abstract]          
Available-for-sale - Current 4,881   4,881   4,554
Available-for-sale - Noncurrent 8,611   8,611   7,570
Mortgage- and asset-backed securities [Member]
         
Trading Securities [Abstract]          
Trading - Current 0   0   0
Trading - Noncurrent 198   198   120
Available-for-sale Securities [Abstract]          
Available-for-sale - Current 1,115   1,115   1,157
Available-for-sale - Noncurrent 327   327   241
Auction rate securities [Member]
         
Available-for-sale Securities [Abstract]          
Available-for-sale - Current 0   0   0
Available-for-sale - Noncurrent 84   84   118
Common and preferred stock [Member]
         
Available-for-sale Securities [Abstract]          
Available-for-sale - Current 23   23   57
Available-for-sale - Noncurrent 2,268   2,268   2,030
Equity funds [Member]
         
Available-for-sale Securities [Abstract]          
Available-for-sale - Current 0   0   0
Available-for-sale - Noncurrent 1,173   1,173   1,126
Debt funds [Member]
         
Available-for-sale Securities [Abstract]          
Available-for-sale - Current 2,522   2,522   1,958
Available-for-sale - Noncurrent 2,740   2,740   1,716
Fair Value Option [Abstract]          
Fair value option - Current 0   0   0
Fair value option - Noncurrent 539   539   520
Increases in fair value recognized in investment income $ 8 $ 17 $ 18 $ 22