Compensation and Benefit Plans (Plan Assets - Changes in Level 3 Fair Value) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Postretirement Benefits Other Than Pensions
Change in plan assets
Fair value of plan assets at beginning of year			$ 1,800
Actual return on plan assets:
Fair value of plan assets at end of year	2,086	2,065	1,800
Postretirement Benefits Other Than Pensions \| Level 3
Change in plan assets
Fair value of plan assets at beginning of year	164	166
Actual return on plan assets:
Relating to assets still held at end of period	18	24
Relating to assets sold during the period	(1)	5
Purchases	9	23
Dispositions	(85)	(54)
Transfers in and/or out of Level 3	0	0
Fair value of plan assets at end of year	105	164
Pension Plans
Change in plan assets
Fair value of plan assets at beginning of year			3,542
Actual return on plan assets:
Fair value of plan assets at end of year	3,454	3,477	3,542
Pension Plans \| Level 3
Change in plan assets
Fair value of plan assets at beginning of year	390	414
Actual return on plan assets:
Relating to assets still held at end of period	114	61
Relating to assets sold during the period	(44)	10
Purchases	13	45
Dispositions	(184)	(140)
Transfers in and/or out of Level 3	0	0
Fair value of plan assets at end of year	$ 289	$ 390

Purchases of plan assets that occurred during the period.

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- Definition

Actual return on plan assets, separately identifying the amount related to assets sold during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(iv)(02)(A)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)(iv)(02)(A)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e2446-114920

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- Definition

Actual return on plan assets, separately identifying the amount related to assets still held at the reporting date.

+ References

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- Definition

The amount of decrease in the plan assets attributed to the sale, liquidation, spin-off or other divestiture of a corporate division or subsidiary.

+ References

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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 non-benefit obligations may be considered as reductions of plan assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Section 35

-Paragraph 50

-URI http://asc.fasb.org/extlink&oid=29635418&loc=d3e12355-114930

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- Definition

Transfers in and out of Level 3. For example, transfers due to changes in the observability of significant inputs.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(iv)(02)(C)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)(iv)(02)(C)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e2446-114920

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