XML 51 R38.htm IDEA: XBRL DOCUMENT v3.4.0.3
Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Mar. 31, 2016
Mar. 31, 2015
Sep. 30, 2015
Goodwill And Intangible Assets [Line Items]          
Goodwill $ 155   $ 155   $ 154
Amortization expense estimated for year one 9   9    
Amortization expense estimated for year two 9   9    
Amortization expense estimated for year three 9   9    
Amortization expense estimated for year four 9   9    
Amortization expense estimated for year five 9   9    
Cost of Sales and Selling and Administrative Expenses [Member]          
Goodwill And Intangible Assets [Line Items]          
Amortization of intangible assets $ 2 $ 4 $ 4 $ 8  
Minimum [Member]          
Goodwill And Intangible Assets [Line Items]          
Useful life of intangible assets     14 years    
Maximum [Member]          
Goodwill And Intangible Assets [Line Items]          
Useful life of intangible assets     25 years    
Weighted Average [Member]          
Goodwill And Intangible Assets [Line Items]          
Useful life of intangible assets     19 years