Contingent Liabilities (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Department of Justice Lawsuit Against Pratt and Whitney [Member]
Loss Contingencies [Line Items]
Loss Contingency Lawsuit Filing Date		1999
Loss Contingency Allegations		As previously disclosed, the United States Government sued us in 1999 in the United States District Court for the Southern District of Ohio, claiming that Pratt & Whitney violated the civil False Claims Act and common law. The claims relate to the “Fighter Engine Competition” between Pratt & Whitney's F100 engine and General Electric's F110 engine. The government alleged that it overpaid for F100 engines under contracts awarded by the U.S. Air Force in fiscal years 1985 through 1990 because Pratt & Whitney inflated its estimated costs for some purchased parts and withheld data that would have revealed the overstatements. At trial, which ended in April 2005, the government claimed Pratt & Whitney's liability to be approximately $624 million.
Loss Contingency Actions Taken By Court Arbitrator Or Mediator		On August 1, 2008, the trial court held that the Air Force had not suffered any actual damages because Pratt & Whitney had made significant price concessions after the alleged overstatements were made. However, the trial court judge found that Pratt & Whitney violated the False Claims Act due to inaccurate statements contained in its 1983 initial engine pricing proposal. In the absence of actual damages, the trial court awarded the government the maximum civil penalty of $7,090,000, or $10,000 for each of the 709 invoices Pratt & Whitney submitted in 1989 and later under the contracts.
Loss Contingency Actions Taken By Plaintiff And Defendant		In September 2008, both the government and UTC appealed the decision to the United States Court of Appeals for the Sixth Circuit. In November 2010, the Sixth Circuit affirmed Pratt & Whitney's liability for the civil penalty under the False Claims Act, but remanded the case to the trial court for further proceedings on the issues of False Claims Act damages and common law liability and damages.
Loss Contingency, Additional Actions Taken by Court, Arbitrator or Mediator		On June 18, 2012, the trial court found that Pratt & Whitney had breached obligations imposed by common law based on the same conduct with respect to which the court previously found liability under the False Claims Act. Under the common law claims, the U.S. Air Force seeks damages for events occurring before March 3, 1989, which are not recoverable under the False Claims Act.
Loss Contingency, Settlement Agreement, Terms		On June 17, 2013, the trial court awarded the government approximately $473 million in damages and penalties, plus prejudgment interest in an amount to be determined. On July 1, 2013, the trial court, after determining the amount of prejudgment interest, entered judgment in favor of the government in the amount of approximately $664 million. The trial court also awarded post-judgment interest on the full amount of the judgment to accrue from July 2, 2013, at the federal variable interest rate determined pursuant to 28 U.S.C. § 1961. The judgment included four different components: (1) common law damages of approximately $109 million; (2) prejudgment interest on common law damages of approximately $191 million; (3) False Claims Act treble damages of approximately $357 million; and (4) the civil penalty of approximately $7 million. The penalty component of the judgment previously was affirmed by the United States Court of Appeals in 2010.
Loss Contingency Damages Sought		624
Loss Contingency, Period of Occurrence		fiscal years 1985 through 1990
Loss Contingency Actions Taken By Defendant		We filed an appeal from the judgment to the United States Court of Appeals for the Sixth Circuit on August 26, 2013. On April 6, 2015, the Sixth Circuit reversed the trial court’s decision and vacated the prior damages award, noting that the government did not prove any damages. The court rejected as a matter of law the evidence submitted by the government on damages and remanded the case to the trial court to decide in the first instance whether the government should have another opportunity to prove that it suffered any actual damages. On July 17, 2015, the case returned to the District Court, at which time we filed a motion for entry of judgment, seeking a judgment of zero actual damages. The government responded by filing a motion on August 28, 2015, in which it abandoned its claim for actual damages, but now seeks a judgment of approximately $85 million, representing (1) disgorgement of UTC’s alleged profits in fiscal year 1985, the first year of the multi-year engine competition, (2) prejudgment interest and (3) the civil penalty. We continue to believe that the government suffered no actual damages as a result of the inaccurate statements made in 1983. We also believe that there is no basis for the government’s new profit disgorgement claim. Accordingly, we continue not to accrue a reserve beyond the approximately $7 million civil penalty referenced above.
Loss Contingency Settlement Agreement Date		6/17/2013
Loss Contingency Damages Awarded Value, Not Including Interest		$ 473
Loss Contingency, Damages Awarded, Value		$ 664
U.S. Defense Contract Management Agency Claim Against Pratt & Whitney [Member]
Loss Contingencies [Line Items]
Loss Contingency Lawsuit Filing Date		December 24, 2013
Loss Contingency Allegations		By letter dated December 24, 2013, a Divisional Administrative Contracting Officer of the United States Defense Contract Management Agency asserted a claim and demand for payment of approximately $211 million against Pratt & Whitney. The claim is based on Pratt & Whitney's alleged noncompliance with cost accounting standards from January 1, 2005 to December 31, 2012, due to its method of determining the cost of collaborator parts used in the calculation of material overhead costs for government contracts.
Loss Contingency Damages Sought		$211 million
Loss Contingency Actions Taken By Defendant		We believe this claim is without merit. On March 18, 2014, Pratt & Whitney filed an appeal to the Armed Services Board of Contract Appeals.
German Tax Office Against Otis [Member]
Loss Contingencies [Line Items]
Loss Contingency Lawsuit Filing Date		August 3, 2012
Loss Contingency Allegations		As previously disclosed, UTC has been involved in administrative review proceedings with the German Tax Office, which concern approximately €215 million (approximately $241 million) of tax benefits that we have claimed related to a 1998 reorganization of the corporate structure of Otis operations in Germany. Upon audit, these tax benefits were disallowed by the German Tax Office. UTC estimates interest associated with the aforementioned tax benefits is an additional approximately €118 million (approximately $133 million).
Loss Contingency Actions Taken By Plaintiff And Defendant		On August 3, 2012, we filed suit in the local German Tax Court (Berlin-Brandenburg). In 2008 the German Federal Tax Court (FTC) denied benefits to another taxpayer in a case involving a German tax law relevant to our reorganization. The determination of the FTC on this other matter was appealed to the European Court of Justice (ECJ) to determine if the underlying German tax law is violative of European Union principles. On September 17, 2009, the ECJ issued an opinion in this case that is generally favorable to the other taxpayer and referred the case back to the FTC for further consideration of certain related issues. In May 2010, the FTC released its decision, in which it resolved certain tax issues that may be relevant to our suit and remanded the case to a lower court for further development. In 2012, the lower court decided in favor of the other taxpayer and the German Government again appealed the findings to the FTC. In November 2014, the FTC ruled in favor of the German Government, and against the other taxpayer. We believe that the FTC decision in the case involving the other taxpayer is not determinative of the outcome in our case, and we will continue vigorously to litigate the matter. However, in light of the FTC decision in the case involving the other taxpayer, we fully accrued for the matter during the quarter ended December 31, 2014.
Loss Contingency Damages Sought		€215 million (approximately $241 million)
Loss Contingency Actions Taken By Defendant		While we continue to litigate the matter at the local German Tax Court, UTC made tax and interest payments to German tax authorities of €38 million (approximately $42 million) in the quarter ended September 30, 2015.  UTC has made aggregate tax and interest payments to the German tax authorities of €275 million (approximately $300 million) through September 30, 2015 (including the payments noted in the immediately preceding sentence) to avoid additional interest accruals pending final resolution of this matter.
Loss Contingency, Interest		€118 million (approximately $133 million)
Loss Contingency, Interest Paid	€38 million (approximately $42 million)	€275 million (approximately $300 million)