Inventories and Contracts in Progress (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Raw materials	$ 2,189	$ 2,040
Work-in-process	3,453	2,787
Finished goods	3,715	3,305
Contracts in progress	10,417	9,395
Inventory before payments and billings	19,774	17,527
Progress payments, secured by lien, on U.S. Government contracts	224	130
Billings on contracts in progress	9,467	8,693
Inventories and contracts in progress, net	10,083	8,704
Inventory [Line Items]
Inventory Costs in Excess of Average Cost Per Unit	357	233
UTC Aerospace Systems [Member]
Inventory [Line Items]
Other Inventory, Capitalized Costs, Gross	$ 130	$ 140

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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 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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