Acquisitions, Dispositions, Goodwill and Other Intangible Assets (Variable Interest Entity) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014
Variable Interest Entity [Line Items]
Current Assets	$ 1,855
Noncurrent Assets	1,184
Total Assets	3,039
Current Liabilities	2,141
Noncurrent Liabilities	1,209
Total Liabilities	$ 3,350

The carrying amount of the consolidated Variable Interest Entity's assets included in the reporting entity's statement of financial position.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (bb)

-URI http://asc.fasb.org/extlink&oid=28200181&loc=d3e5710-111685

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying amount of the consolidated Variable Interest Entity's liabilities included in the reporting entity's statement of financial position.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying amount of the consolidated Variable Interest Entity's current assets included in the reporting entity's statement of financial position.

+ References

No definition available.

+ Details

Name:	utx_VariableInterestEntityConsolidatedCarryingAmountCurrentAssets
Namespace Prefix:	utx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying amount of the consolidated Variable Interest Entity's current liabilities included in the reporting entity's statement of financial position.

+ References

No definition available.

+ Details

Name:	utx_VariableInterestEntityConsolidatedCarryingAmountCurrentLiabilities
Namespace Prefix:	utx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying amount of the consolidated Variable Interest Entity's noncurrent assets included in the reporting entity's statement of financial position.

+ References

No definition available.

+ Details

Name:	utx_VariableInterestEntityConsolidatedCarryingAmountNoncurrentAssets
Namespace Prefix:	utx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying amount of the consolidated Variable Interest Entity's noncurrent liabilities included in the reporting entity's statement of financial position.

+ References

No definition available.

+ Details

Name:	utx_VariableInterestEntityConsolidatedCarryingAmountNoncurrentLiabilities
Namespace Prefix:	utx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant