Receivables, Net (Tables)
 6 Months Ended
Mar. 31, 2016
Receivables [Abstract]  
Schedule of Accounts Receivable
Receivables, net are summarized as follows:
(in millions)
March 31,
2016
 
September 30,
2015
Billed
$
729

 
$
752

Unbilled
477

 
403

Less progress payments
(111
)
 
(110
)
Total
1,095

 
1,045

Less allowance for doubtful accounts
(7
)
 
(7
)
Receivables, net
$
1,088

 
$
1,038