Guarantees and Product Warranty (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Movement in Standard Product Warranty Accrual
Warranty liability, beginning balance	$ 1,426us-gaap_ProductWarrantyAccrual	$ 1,367us-gaap_ProductWarrantyAccrual
Reduction in liability (payments)	(225)us-gaap_ProductWarrantyAccrualPayments	(1,071)us-gaap_ProductWarrantyAccrualPayments
Increase in liability (new warranties)	188	1,130
Warranty liability, ending balance	1,389us-gaap_ProductWarrantyAccrual	1,426us-gaap_ProductWarrantyAccrual
Product warranty accrual, preexisting, increase (decrease)		$ 170

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Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard and extended warranty protection rights granted to customers.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.15(5))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 15

-Subparagraph 5

-Article 9

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph ((c)(5))

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

+ Details

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- Definition

Represents the aggregate decrease in the liability related to payments to satisfy claims for standard and extended product warranties.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph ((c)(2))

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

+ Details

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- Definition

Represents the aggregate Increase or Decrease in the liability during the reporting period for accruals related to preexisting standard and extended product warranties (including adjustments for changes in estimates).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph ((c)(4))

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

+ Details

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- Definition

Represents the aggregate increase in the liability for accruals related to standard and extended product warranties issued during the reporting period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph ((c)(3))

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

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