v3.3.0.814
Income Taxes - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
Sep. 30, 2015
Sep. 30, 2014
Sep. 30, 2013
Tax Credit Carryforward [Line Items]      
US income before taxes $ 7,214 $ 6,140 $ 5,992
U.S. federal statutory rate 35.00% 35.00% 35.00%
Income tax provision, percent 30.00% 30.00% 31.00%
Unrecognized Tax Benefits, Period Increase (Decrease) $ 296    
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions 239 $ 0 $ 0
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount   264  
Prior years U.S. domestic production activities deduction 0 191 0
Income taxes receivable included in prepaid and other current assets 77 91  
Income Taxes Receivable 627 597  
Income taxes payable included in accrued taxes as part of accrued liabilities 75 73  
Accrued income taxes included in other long-term liabilities [1] 752 855  
Cumulative undistributed earnings of the Company's international subsidiaries intended to be reinvested indefinitely outside the U.S 6,400    
Decreased Singapore tax as a result of the tax incentive agreement $ (192) $ (168) $ (158)
Benefit of the tax incentive agreement on diluted net income per share $ 0.08 $ 0.07 $ 0.06
Total unrecognized tax benefits exclusive of interest and penalties $ 1,051 $ 1,303 $ 1,023
Unrecognized tax benefits, if recognized, would reduce the effective tax rate in a future period 859 1,100  
Interest expense included in interest expense and administrative and other (6) 10 9
Accrued penalties related to uncertain tax positions 1 2  
Reversal of penalties upon the effective settlement of uncertainties surrounding the timing of certain deductions     4
Accrued interest related to uncertain tax positions in other long term liabilities 33 39  
Accrued penalties related to uncertain tax positions in other long term liabilities 6 5  
Non United States Customers      
Tax Credit Carryforward [Line Items]      
US income before taxes 2,400 $ 2,300 $ 2,000
Federal      
Tax Credit Carryforward [Line Items]      
Net operating loss carryforwards 30    
State and Local Jurisdiction      
Tax Credit Carryforward [Line Items]      
Net operating loss carryforwards 19    
Foreign Country      
Tax Credit Carryforward [Line Items]      
Net operating loss carryforwards $ 177    
[1] The decrease in non-current accrued income taxes is primarily related to decreases in liabilities for uncertain tax positions.