Financial Instruments (Narrative) (Details) (USD $) In Billions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Notes to Condensed Consolidated Financial Statements [Abstract]
Four Quarter Rolling Average of Notional Amount of Foreign Exchange Contracts Hedging Foreign Currency Transactions	$ 12.5	$ 11.8

Four quarter rolling average notional amount of all foreign currency derivatives designated as hedging instruments in cash flow hedges. Notional amount refers to the number of currency units specified in the foreign currency derivative contract.

No definition available.

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