Inventories and Contracts in Progress (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Raw materials	$ 2,444,000,000	$ 2,038,000,000
Work-in-process	2,292,000,000	3,366,000,000
Finished goods	4,332,000,000	3,845,000,000
Contracts in progress	0	10,205,000,000
Inventory before payments and billings	9,068,000,000	19,454,000,000
Progress payments, secured by lien, on U.S. Government contracts	0	236,000,000
Billings on contracts in progress	0	9,337,000,000
Inventories and contracts in progress, net	9,068,000,000	9,881,000,000
Inventory [Line Items]
Inventory Costs in Excess of Average Cost Per Unit	0	438,000,000
UTC Aerospace Systems [Member]
Inventory [Line Items]
Other Inventory, Capitalized Costs, Gross	$ 0	$ 127,000,000

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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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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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