CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (Unaudited) (Parenthetical) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Apr. 30, 2017
Apr. 30, 2016
Apr. 30, 2017
Apr. 30, 2016
Other comprehensive income (loss), tax, parenthetical disclosures [Abstract]        
Unrealized gain (loss) on investments, tax $ 1 $ 0 $ 0 $ 1
Unrealized gain (loss) on derivative instruments, tax 0 1 (1) 0
Amounts reclassified into earnings related to derivative instruments, tax (1) (1) (1) (2)
Foreign currency translation, tax 0 0 0 0
Net defined benefit pension cost and post retirement plan costs, tax [Abstract]        
Change in actuarial net loss, tax (5) (4) (18) (10)
Change in net prior service credit, tax $ 2 $ 2 $ 4 $ 5