Retirement Benefits (Details 3) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Amounts recorded in accumulated other comprehensive loss (Table Amounts) [Abstract]
Unamortized benefit plan costs	$ (3,487)	$ (2,762)
Pension Benefits
Amounts recorded in accumulated other comprehensive loss (Table Amounts) [Abstract]
Net actuarial loss	(6,131)	(4,246)
Prior service (cost) credit	537	(194)
Income tax benefits related to above items	2,215	1,752
Unamortized benefit plan costs	(3,379)	(2,688)
Medical and Life Benefits
Amounts recorded in accumulated other comprehensive loss (Table Amounts) [Abstract]
Net actuarial loss	(331)	(361)
Prior service (cost) credit	149	238
Income tax benefits related to above items	74	49
Unamortized benefit plan costs	$ (108)	$ (74)

For prior service costs, the amount related to the pretax cost of benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation, which has not yet been recognized as components of net periodic benefit cost. For net transition assets, the original amount of transition assets as of the date FAS 87 or 106 was initially applied, (a) the fair value of plan assets plus any recognized accrued pension or other postretirement benefit cost or less any recognized prepaid pension or other postretirement benefit cost in excess of (b) the benefit obligation, the portion of which has yet to be recognized as components of net periodic benefit cost. For net transition obligations, the original amount of transition obligations as of the date FAS 87 or 106 was initially applied, (a) the benefit obligation in excess of (b) the fair value of plan assets plus any recognized accrued pension or other postretirement benefit cost or less any recognized prepaid pension or other postretirement benefit cost, the portion of which has yet to be recognized as components of net periodic benefit cost. All amounts are pretax.

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The total of net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e637-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

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-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e681-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 130

-Paragraph 26

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e653-108580

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph i

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 158

-Paragraph 7

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

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-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

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- Definition

The pretax net amount of gains and losses that are not yet recognized as a component of net periodic benefit cost, and that are recognized as increases or decreases in other comprehensive income as they arise. Gains and losses are due to 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.

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