XML 82 R68.htm IDEA: XBRL DOCUMENT v3.8.0.1
Fair Value Measurements (Schedule Of Available For Sale Securities) (Details) - USD ($)
$ in Millions
Mar. 31, 2018
Sep. 30, 2017
U.S. treasury and agency    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Amortized Cost Basis $ 46 $ 47
Fair Value 46 47
Unrealized Gain (Loss) 0 0
Corporate and asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Amortized Cost Basis 52 51
Fair Value 52 51
Unrealized Gain (Loss) $ 0 $ 0