Investments (Schedule Of Ownership Percentages And Balances Of Equity Method Investments) (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Equity method investments	[1]	$ 1,214	$ 1,242
Defense, Space & Security [Member] | United Launch Alliance [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		50.00%	50.00%
Equity method investments		$ 889	$ 914
Commercial Airplanes, Defense, Space & Security, and Global Services [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments		$ 325	$ 328

[1] Dividends received were $247 and $314 during 2017 and 2016. Retained earnings at December 31, 2017 include undistributed earnings from our equity method investments of $307.