Postretirement Benefits - Summary of Changes in the Defined Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2012
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Curtailments	$ 4us-gaap_DefinedBenefitPlanCurtailments
Pension Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligations at beginning of year			3,943	4,492
Amendments			0	3
Service cost			12	20	17
Interest on obligations			158	143	169
Actuarial loss (gain)			(176)	334
Curtailments			2	33
Contractual termination benefits			23	0
Currency translation			(49)	15
Plan participants' contributions			0	0
Subsidy receipts			0	0
Benefits paid			318	333
Benefit obligations at end of year	3,943	4,041	4,041	3,943	4,492
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year			2,519	2,411
Actual return on plan assets			206	284
Currency translation			42	(22)
Employer contributions		164	164	165
Benefits paid			304	319
Fair value of plan assets at end of year	2,519	2,627	2,627	2,519	2,411
Funded status at year end	(1,424)	(1,414)	(1,414)	(1,424)
Health and Life Insurance Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligations at beginning of year			1,674	1,866
Amendments			0	0
Service cost			5	7	7
Interest on obligations			68	62	83
Actuarial loss (gain)			(319)	142
Curtailments			0	0
Contractual termination benefits			2	0
Currency translation			0	0
Plan participants' contributions			40	28
Subsidy receipts			34	41
Benefits paid			185	188
Benefit obligations at end of year	1,674	1,957	1,957	1,674	1,866
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year			447	437
Actual return on plan assets			26	66
Currency translation			0	0
Employer contributions			2	3
Benefits paid			60	59
Fair value of plan assets at end of year	447	415	415	447	437
Funded status at year end	$ (1,227)	$ (1,542)	$ (1,542)	$ (1,227)

Defined Benefit Plan Change In Fair Value Of Plan Assets Benefits Paid

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The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Actual Return on Plan Assets (Component of Net Periodic Postretirement Benefit Cost)

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-Glossary Actual Return on Plan Assets (Component of Net Periodic Pension Cost)

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Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan.

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- Definition

1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

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-Glossary Projected Benefit Obligation

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-Name Accounting Standards Codification

-Glossary Accumulated Postretirement Benefit Obligation

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The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.

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-Glossary Postretirement Benefits

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- Definition

The increase in the fair value of plan assets from contributions made by the employer.

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The amount of contributions made by plan participants. This item represents a periodic increase to the plan obligation and an increase to plan assets.

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- Definition

The amount of decrease that is related to an event that significantly reduces the expected years of future service of present employees or eliminates for a significant number of employees the accrual of defined benefits for some or all of their future services.

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-Glossary Plan Curtailment

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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

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Amount of gain (loss) from foreign currency exchange rate changes for benefit obligation for plans of a foreign operation whose functional currency is not the reporting currency.

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The amount of increase or decrease in plan assets attributed to foreign currency changes. The effects of foreign currency exchange rate changes that are to be disclosed are those applicable to plans of a foreign operation whose functional currency is not the reporting currency.

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The funded status is measured as the difference between the fair value of plan assets and the benefit obligation. Will normally be the same as the net Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total.

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Amount of the period's gross receipts received from the prescription drug subsidy, which is to be used in the roll forward of the accumulated postretirement benefit obligation of an applicable postretirement benefit plan.

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The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

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The amount of increase or decrease due to a change in the terms of an existing plan or the initiation of a new plan. A plan amendment may increase or decrease benefits, including those attributed to years of service already rendered.

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The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

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The amount of increase related to special termination benefits offered to and accepted by employees in connection with their termination of employment that are only offered for a short period of time. A situation involving termination benefits may also involve a curtailment.

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