CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS (PARENTHETICAL) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Apr. 30, 2016
Apr. 30, 2015
Apr. 30, 2016
Apr. 30, 2015
Income tax benefit from discontinued operations $ 0 $ 0 $ 0 $ (2)