Acquisitions, Dispositions, Goodwill and Other Intangible Assets (Intangible Assets) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 17,611	$ 17,525
Accumulated Amortization	4,140	4,142
Unamortized: Trademarks and Other	2,100	2,177
Total Intangible Assets Gross Excluding Goodwill	19,711	19,702
Amortization of Intangible Assets	179us-gaap_AmortizationOfIntangibleAssets
Service portfolios [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	1,975	2,103
Accumulated Amortization	1,254	1,309
Patents and trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	366	361
Accumulated Amortization	189	190
IAE collaboration [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	3,003	2,872
Accumulated Amortization	32	20
Customer relationships and other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	12,267	12,189
Accumulated Amortization	$ 2,665	$ 2,623

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

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-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

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

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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

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-Topic 350

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

+ References

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Amount before accumulated amortization of intangible assets, excluding goodwill.

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