Condensed Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Mar. 31, 2016
Mar. 31, 2015
Statement of Comprehensive Income [Abstract]        
Pension and other retirement benefits adjustments tax benefit $ 8 $ 6 $ 16 $ 13
Foreign currency cash flow hedge adjustment tax benefit (expense) $ 1 $ 1 $ 1 $ (1)