Retirement Benefits (Details 4) (USD $) In Millions	12 Months Ended
Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Change in Plan Assets
Fair value of plan assets at end of year	$ 21,013	$ 19,027
Pension Benefits
Change in Projected Benefit Obligation [Abstract]
Projected benefit obligation at beginning of year	20,661	19,391
Service cost	531	547	591
Interest cost	1,212	1,180	1,179
Plan participants' contributions	10	10
Plan amendments	0	4
Actuarial loss (gain)	633	755
Benefits paid	(1,176)	(1,261)
Other	(51)	35
Projected benefit obligation at end of year	21,820	20,661	19,391
Change in Plan Assets
Fair value of plan assets at beginning of year	18,184	16,204
Gain/(loss) on plan assets	2,320	2,562
Employer contributions	789	657
Other	(46)	12
Fair value of plan assets at end of year	20,081	18,184	16,204
Funded status	(1,739)	(2,477)
Medical and Life Benefits
Change in Projected Benefit Obligation [Abstract]
Projected benefit obligation at beginning of year	2,104	2,056
Service cost	34	34	40
Interest cost	117	124	127
Plan participants' contributions	82	91
Plan amendments	0	0
Actuarial loss (gain)	(27)	20
Benefits paid	(222)	(238)
Other	16	17
Projected benefit obligation at end of year	2,104	2,104	2,056
Change in Plan Assets
Fair value of plan assets at beginning of year	843	718
Gain/(loss) on plan assets	108	126
Employer contributions	105	129
Other	16	17
Fair value of plan assets at end of year	932	843	718
Funded status	$ (1,172)	$ (1,261)

Change in Plan Assets.

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- Definition

Component of change in benefit obligation that is not otherwise reflected in the taxonomy.

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Component of change in plan assets that is not otherwise reflected in the taxonomy.

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- Definition

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph d(iv)(b)(i)

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 106
-Paragraph 518

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 264

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph b

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- Definition

The net increase or decrease of changes in the value of either the benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption, or the consequence of a decision to temporarily deviate from the substantive plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 106
-Paragraph 518

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 264

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph a

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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. The projected benefit obligation is measured using assumptions as to future compensation levels if the pension benefit formula is based on those future compensation levels (pay-related, final-pay, final-average-pay, or career-average-pay plans). For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same. 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. Prior to an employee's full eligibility date, the accumulated postretirement benefit obligation as of a particular date for an employee is the portion of the expected postretirement benefit obligation attributed to that employee's service rendered to that date; on and after the full eligibility date, the accumulated and expected postretirement benefit obligations for an employee are the same.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph a

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 6
-Subparagraph a

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph E1

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph a, b

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 106
-Paragraph 518

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 264

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS106-2
-Paragraph 22

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

The amount of contributions made by the employer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph b

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- Definition

The amount of contributions made by plan participants. Under a contributory plan active employees or retirees contribute part of the cost. In some contributory plans, those wishing to be covered must contribute; in others, the contributions result in increased benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph b

+ Details

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- Definition

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 nonbenefit obligations may be considered as reductions of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph b

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph d(iv)(b)(i)

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 49

+ Details

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph c

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- Definition

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.

+ References

+ Details

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- Definition

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.

+ References

+ Details

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- Definition

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.

+ References

+ Details

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