Postretirement Benefits - Schedule of Amounts Recognized in Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Oct. 31, 2014	Oct. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Noncurrent liability	$ 2,862	$ 2,564
Net liability recognized	2,955	2,652
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Current liability	15	14
Noncurrent liability	1,399	1,410
Net liability recognized	1,414	1,424
Net actuarial loss	(2,019)	(1,947)
Net prior service cost (benefit)	1	1
Net amount recognized	2,020	1,948
Amortization of prior service cost (benefit)	0
Amortization of cumulative losses	98
Health and Life Insurance Benefits
Defined Benefit Plan Disclosure [Line Items]
Current liability	79	73
Noncurrent liability	1,463	1,154
Net liability recognized	1,542	1,227
Net actuarial loss	(664)	(354)
Net prior service cost (benefit)	(6)	(10)
Net amount recognized	658	344
Amortization of prior service cost (benefit)	(4)
Amortization of cumulative losses	$ 39