Basis of Presentation and Summary of Accounting Principles (Schedule of change in accounting estimates) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in Accounting Estimate [Line Items]
Operating profit (loss)									$ (1,889)	$ 4,914	$ 2,877
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	$ 146	$ 151	$ (3,844)	$ 438	$ 657	$ 958	$ 1,183	$ 712	$ (3,109)	$ 3,510	$ 1,216
Income (loss) from continuing operations attributable to common shareowners	$ 0.10	$ 0.10	$ (2.56)	$ 0.50	$ 0.76	$ 1.11	$ 1.37	$ 0.83	$ (2.29)	$ 4.06	$ 1.50
Contracts Accounted for under Percentage of Completion
Change in Accounting Estimate [Line Items]
Operating profit (loss)									$ (643)	$ (69)	$ (50)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent									$ (508)	$ (55)	$ (40)
Income (loss) from continuing operations attributable to common shareowners									$ (0.37)	$ (0.06)	$ (0.05)