Inventories and Contracts in Progress (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 2,058	$ 2,056
Work-in-process	4,006	3,596
Finished goods	3,941	3,776
Contracts in progress	8,210	8,189
Inventory before payments and billings	18,215utx_InventoryBeforePaymentsAndBillings	17,617utx_InventoryBeforePaymentsAndBillings
Progress payments, secured by lien, on U.S. Government contracts	434	300
Billings on contracts in progress	7,445	7,452
Inventories and contracts in progress, net	10,336us-gaap_InventoryNet	9,865us-gaap_InventoryNet
UTC Aerospace Systems [Member]
Inventory [Line Items]
Other Inventory, Capitalized Costs, Gross	$ 131	$ 141

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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

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Amount before valuation and LIFO reserves, and progress payments, of inventory associated with long-term contracts, expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of unprocessed items to be consumed in the manufacturing or production process.

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Carrying amount, net of reserves and adjustments, as of the balance sheet date of merchandise or goods which are partially completed. This inventory is generally comprised of raw materials, labor and factory overhead costs, which require further materials, labor and overhead to be converted into finished goods, and which generally require the use of estimates to determine percentage complete and pricing.

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Gross amount of an expenditure that is incurred which is not expensed in the current period but rather capitalized as a component of inventory.

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Carrying amount (lower of cost or market) as of the balance sheet date of inventories, including those associated with long-term contracts or programs, before payments and billings.

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Amount of advances received from customers, excluding U.S. Government customers, under long-term contracts which have been offset against inventory accounts at the balance sheet date.

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Amount of advances received from U.S. Government customers under long-term contracts which have been offset against inventory accounts at the balance sheet date.

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