Receivables, Net (Details) - USD ($)
$ in Millions
6 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Sep. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Billed $ 699   $ 748
Unbilled 505   439
Less progress payments (63)   (87)
Total 1,141   1,100
Less allowance for doubtful accounts (6)   (6)
Receivables, net 1,135   1,094
Receivables, net due from equity affiliates 90   $ 68
Net Cash Provided by Operating Activities, Continuing Operations 1 $ 45  
Sales Under Factoring Agreements [Member]      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Net Cash Provided by Operating Activities, Continuing Operations $ 136 $ 9