Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_BusinessAcquisitionProFormaInformationNonrecurringAdjustmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Name:	us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The total cost of acquired entities and interest in affiliates including the cash paid to shareholders, fair value of debt and equity securities issued to shareholders, the fair value of the liabilities assumed, and direct costs of the acquisitions and interest in affiliates.

No definition available.

Name:	utx_AcquisitionCostOfAcquiredEntitiesAndInterestInAffiliates
Namespace Prefix:	utx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Business Acquisition UTC stock payable shares

No definition available.

Name:	utx_BusinessAcquisitionUTCstockpayableshares
Namespace Prefix:	utx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Portfolio separation costs

No definition available.

Name:	utx_Portfolioseparationcosts
Namespace Prefix:	utx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Reflects adjustments for the elimination of amortization of prior service cost and actuarial loss amortization, which was recorded by Rockwell Collins, as a result of fair value purchase accounting, net of the impact of the revised pension and post-retirement benefit (expense) as determined under UTC’s plan assumptions.

No definition available.

Name:	utx_ProFormaNonrecurringAdjustmentAdjustmenttonetperiodicpensioncost
Namespace Prefix:	utx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Reflects the additional amortization of the acquired Rockwell Collins intangible assets recognized at fair value in purchase accounting and eliminates the historical Rockwell Collins intangible asset amortization expense.

No definition available.

Name:	utx_ProFormaNonrecurringAdjustmentAmortizationofacquiredRockwellCollinsintangibleassetsnet
Namespace Prefix:	utx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Reflects the amortization expense on the Rockwell Collins inventory step up which would be completed within the first two quarters of 2017 and eliminated the inventory step-up amortization recorded by UTC in 2018. Additionally, this adjustments reflects the amortization of the fixed asset fair value adjustment as of the acquisition date.

No definition available.

Name:	utx_ProFormaNonrecurringAdjustmentAmortizationofinventoryandfixedassetfairvalueadjustment
Namespace Prefix:	utx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Reflects the additional amortization of liabilities recognized for acquired contracts with terms less favorable than could be realized in market transactions as of the acquisition date and eliminates Rockwell Collins historical amortization of these liabilities.

No definition available.

Name:	utx_ProFormaNonrecurringAdjustmentUtilizationofcontractualcustomerobligation
Namespace Prefix:	utx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Shares of common stock distributed in the Distribution

No definition available.

Name:	utx_SharesOfCommonStockDistributedInTheDistribution
Namespace Prefix:	utx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_StatementBusinessSegmentsAxis=utx_UTCClimateControlsAndSecurityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementBusinessSegmentsAxis=utx_OtisMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_SellingGeneralAndAdministrativeExpensesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_InterestExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_IncomeStatementLocationAxis=utx_IncometaxexpenseDomain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_IncomeStatementLocationAxis=utx_DebtExtinguishmentCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: