Postretirement Benefits Components of Net Periodic Benefit Expense (Income) and Other Amounts Recognized in Other Comprehensive Loss (Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Oct. 31, 2011	Jul. 31, 2011	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2009
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net postretirement benefits expense			$ 169	$ 179	$ 233
Defined Benefit Plan, Amounts Other changes in plan assets and benefit obligations recognized in other comprehensive loss (income) [Abstract]
Prior service cost (benefit)	302
Pension [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost for benefits earned during the period			17	18	15
Interest on obligations			189	209	234
Amortization of net cumulative loss (gain)			97	98	72
Amortization of prior service cost (benefit)			1	1	1
Curtailments			2	1	6
Contractual termination benefits	3	35	38	1	9
Premiums on pension insurance			6	7	6
Expected return on assets			211	193	189
Net postretirement benefits expense			139	142	154
Defined Benefit Plan, Amounts Other changes in plan assets and benefit obligations recognized in other comprehensive loss (income) [Abstract]
Actuarial net loss (gain)			374	77	713
Amortization of cumulative gain (loss)			(97)	(98)	(72)
Prior service cost (benefit)			0	4	4
Amortization of prior service benefit (cost)			(1)	(1)	(1)
Curtailments			(13)	(3)	0
Currency translation			4	4
Total recognized in other comprehensive loss (income)			267	(17)	644
Total net postretirement benefits expense (income) and other comprehensive loss (income)			406	125	798
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Amortization of prior service cost (benefit)			1
Amortization of cumulative losses			109
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost for benefits earned during the period			8	8	6
Interest on obligations			56	81	117
Amortization of net cumulative loss (gain)			4	8	(2)
Amortization of prior service cost (benefit)			(29)	(20)	(5)
Curtailments			11	2	0
Contractual termination benefits			6	(2)	3
Retrospective payments to retirees			(15)
Premiums on pension insurance			0	0	0
Expected return on assets			41	40	40
Net postretirement benefits expense			30	37	79
Defined Benefit Plan, Amounts Other changes in plan assets and benefit obligations recognized in other comprehensive loss (income) [Abstract]
Actuarial net loss (gain)			566	(127)	180
Amortization of cumulative gain (loss)			(4)	(8)	2
Prior service cost (benefit)			302	(341)	0
Amortization of prior service benefit (cost)			29	20	5
Curtailments			0	0	0
Total recognized in other comprehensive loss (income)			893	(456)	187
Total net postretirement benefits expense (income) and other comprehensive loss (income)			923	(419)	266
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Amortization of prior service cost (benefit)			(5)
Amortization of cumulative losses			$ 37