Date the debt instrument was issued, in CCYY-MM-DD format.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

No definition available.

+ Details

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

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

No definition available.

+ Details

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

- Definition

The portion of the carrying amount of borrowings outstanding as of the balance-sheet date, which accrues interest at a rate subject to change from time to time.

+ References

No definition available.

+ Details

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Namespace Prefix:	utx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of shares issued as a result of long-term debt remarketing.

+ References

No definition available.

+ Details

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

- Definition

Long Term Debt Remarketing, Proceeds

+ References

No definition available.

+ Details

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

- Definition

Date on which the remarketing of a debt instrument took place.

+ References

No definition available.

+ Details

Name:	utx_RemarketingofDebtInstrumentDate
Namespace Prefix:	utx_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The date on which proceeds resulting from the remarketing of a long-term debt issuance are received.

+ References

No definition available.

+ Details

Name:	utx_RemarketingofLongTermDebtDateProceedsReceived
Namespace Prefix:	utx_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date on which outstanding debt was repaid.

+ References

No definition available.

+ Details

Name:	utx_RepaymentofDebtDate
Namespace Prefix:	utx_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=utx_Notes4875Due2015Member
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- Details

Name:	us-gaap_DebtInstrumentAxis=utx_LIBORPlus0500FloatingRateNotesDue2015Member
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Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=utx_JuniorSubordinatedNotes1550Due2022Member
Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_DebtInstrumentAxis=utx_Juniorsubordinatednotes1.778due2018Member
Namespace Prefix:
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- Details

Name:	us-gaap_DebtInstrumentAxis=utx_Notes1.250due2023Member
Namespace Prefix:
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Borrowings and Lines of Credit Borrowings and Lines of Credit (LT Debt Narrative) (Details) € in Millions, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) shares	Dec. 31, 2015 EUR (€) shares	Dec. 31, 2014
Debt Instrument [Line Items]
Long Term Debt Remarketing, Proceeds	$ 1,100
Long Term Debt Remarketing, Number of Shares Issued \| shares	11.3	11.3
Debt Percentage Bearing Variable Interest Rate	5.00%	5.00%	4.00%
Notes 4.150% Due 2045 [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date	May 04, 2015	May 04, 2015
Proceeds from Issuance of Debt	$ 850
Notes 4.875% Due 2015 [Member]
Debt Instrument [Line Items]
Repayment of Debt, Date	May 01, 2015	May 01, 2015
Repayments of Debt	$ 1,200
LIBOR plus 0.500% floating rate notes due 2015
Debt Instrument [Line Items]
Repayment of Debt, Date	Jun. 01, 2015	Jun. 01, 2015
Repayments of Debt	$ 500
Junior Subordinated Notes 1.550% Due 2022 [Member]
Debt Instrument [Line Items]
Remarketing of Debt Instrument, Date	May 04, 2015	May 04, 2015
Junior subordinated notes 1.778% due 2018 [Member]
Debt Instrument [Line Items]
Remarketing of Long Term Debt, Date Proceeds Received	Aug. 03, 2015	Aug. 03, 2015
Long Term Debt Remarketing, Proceeds	$ 1,100
Long Term Debt Remarketing, Number of Shares Issued \| shares	11.3	11.3
Notes 1.250% due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date	May 22, 2015	May 22, 2015
Proceeds from Issuance of Debt \| €		€ 750