Fair Value Measurements - Level 3 Reconciliation (Details) - Guarantees [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2015	Jul. 31, 2014
Fair Value Assets And Liablities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability) Beginning Value	$ (7)	$ (6)	$ (8)	$ (6)
Transfers out of Level 3	0	0	0	0
Issuances	(4)	0	(4)	0
Settlements	1	0	2	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability) Ending Value	(10)	(6)	(10)	(6)
Change in unrealized gains on assets and liabilities still held	$ 0	$ 0	$ 0	$ 0