Fair Value Measurements - Level 3 Reconciliation (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014	Apr. 30, 2013
Guarantees [Member]
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	$ (6)	$ (7)	$ (6)	$ (7)
Transfers out of Level 3	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability) Ending Value	(6)	(7)	(6)	(7)
Change in unrealized gains on assets and liabilities still held	0	0	0	0
Commodity Contract [Member]
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	0	0	0	0
Transfers out of Level 3	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability) Ending Value	0	0	0	0
Change in unrealized gains on assets and liabilities still held	$ 0	$ 0	$ 0	$ 0