Fair Value Measurements - Level 3 Reconciliation (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Oct. 31, 2012		Oct. 31, 2011		Jan. 31, 2012	Jan. 31, 2011
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)	$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	[1]	0	[1]
Fair Value, Level 3 Transfers out, Description	0		0
Issuances	(1)		(6)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability) Ending Value	(7)		(6)
Change in unrealized gains on assets and liabilities still held	0		0
Retained Interest [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	53
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	[1]	0	[1]
Fair Value, Level 3 Transfers out, Description	0		0
Issuances	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0		53
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability) Ending Value	0		0
Change in unrealized gains on assets and liabilities still held	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					(2)	2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	[1]	2	[1]
Fair Value, Level 3 Transfers out, Description	2		0
Issuances	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0		6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability) Ending Value	0		(2)
Change in unrealized gains on assets and liabilities still held	$ 0		$ (2)

[1] For commodity contracts, gains are included in Cost of products sold.