Taxes on Earnings (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Domestic and foreign components of earnings (loss) before taxes
U.S.(1)									$ (2,805)	$ (1,929)	$ (1,758)
Non-U.S.(1)									3,073	2,201	5,618
Earnings from continuing operations before taxes	$ 576	$ 465	$ (116)	$ (657)	$ (301)	$ 125	$ 113	$ 335	268	272	3,860
U.S. federal taxes:
Current									(2,177)	560	940
Deferred									150	(1,366)	(959)
Non-U.S. taxes:
Current									419	64	874
Deferred									(188)	25	(58)
State taxes:
Current									52	(107)	36
Deferred									0	660	(210)
Provision for (benefit from) taxes on earnings	$ 1,348	$ 13	$ (966)	$ (2,139)	$ (679)	$ (160)	$ 591	$ 84	$ (1,744)	$ (164)	$ 623