Summary of Accounting Principles (Details) € in Millions, $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2018 EUR (€)
Accounting Policies [Abstract]
Restricted Cash And Cash Equivalents	$ 60	$ 33	$ 32
Unbilled Contracts Receivable	678	2,770
Contract Receivable Retainage	116	118
Excess Of Replacement Or Current Costs Over Stated LIFO Value	119	106
Operating profit impact of contract adjustments	(50)	(110)	$ (157)
Commercial paper, euro-denominated	$ 858			€ 750
Long-term debt, euro-denominated \| €				€ 4,950
Commercial Aerospace [Member]
Accounting Policies [Abstract]
Unbilled Contracts Receivable		$ 1,109

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Amount billed to customers under long-term contracts or programs that have been withheld because of retainage provisions in a contract.

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The excess of replacement or current cost over the stated LIFO (last in first out) inventory value when the LIFO inventory method is utilized.

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Amount of cash and cash equivalents restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet.

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Euro-denominated Commercial paper - carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

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Long-term debt, euro-denominated

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Operating profit impact of contract adjustments

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