Long-Term Financing Receivables (Reserve and Additional Information) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Long Term Receivables High Credit Risk Percentage	14.00%	13.00%
Financing Receivable Reserve For Credit Losses And Exposure	$ 18	$ 18

A valuation allowance for financing receivables that are expected to be uncollectible and/or contain collateral exposure risk.

No definition available.

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