Financial Instruments - Pre-tax Effect of Derivative Instruments and Related Hedged Items in a Fair Value Hedging Relationship (Details) - Interest rate contracts - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) Recognized in Earnings on Derivative	$ 23	$ 127	$ (202)	$ 294
Gains (Losses) Recognized in Earnings on Related Hedged Item	$ (23)	$ (127)	$ 202	$ (294)