Acquisitions and Divestitures, Goodwill, and Intangible Assets (Changes In Goodwill) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019
Goodwill [Roll Forward]
Goodwill, beginning of period	[2]	$ 19,677	[1]	$ 19,594
Acquisitions/divestitures		137		101	[3]
Other	[4]	239		(18)
Change in reporting unit composition	[5]	0
Goodwill, end of period		20,053	[6]	19,677	[1],[2]
Aerospace
Goodwill [Roll Forward]
Goodwill, beginning of period	[2]	2,831		2,813
Acquisitions/divestitures	[3]	72		3
Other	[4]	162		15
Change in reporting unit composition	[5]	0
Goodwill, end of period		3,065	[6]	2,831	[2]
Marine Systems
Goodwill [Roll Forward]
Goodwill, beginning of period	[2]	297		297
Acquisitions/divestitures	[3]	0		0
Other	[4]	0		0
Change in reporting unit composition	[5]	0
Goodwill, end of period		297	[6]	297	[2]
Combat Systems
Goodwill [Roll Forward]
Goodwill, beginning of period	[2]	2,681		2,633
Acquisitions/divestitures	[3]	65		15
Other	[4]	40		33
Change in reporting unit composition	[5]	0
Goodwill, end of period		2,786	[6]	2,681	[2]
Information Technology
Goodwill [Roll Forward]
Goodwill, beginning of period	[2]	9,700		9,622
Acquisitions/divestitures	[3]	0		77
Other	[4]	46		1
Change in reporting unit composition	[5]	(9,746)
Goodwill, end of period		0	[6]	9,700	[2]
Accumulated impairment loss		536
Mission Systems
Goodwill [Roll Forward]
Goodwill, beginning of period	[2]	4,168		4,229
Acquisitions/divestitures	[3]	0		6
Other	[4]	(9)		(67)
Change in reporting unit composition	[5]	(4,159)
Goodwill, end of period		0	[6]	4,168	[2]
Accumulated impairment loss		1,300
Technologies
Goodwill [Roll Forward]
Goodwill, beginning of period	[2]	0		0
Acquisitions/divestitures	[3]	0		0
Other	[4]	0		0
Change in reporting unit composition	[5]	13,905
Goodwill, end of period		13,905	[6]	$ 0	[2]
Accumulated impairment loss		$ 1,800

[1] *Prior-period information has been restated for the retrospective application of a change in accounting principle related to the amortization of actuarial gains and losses for our qualified U.S. government pension plans, which we adopted in the fourth quarter of 2020. For further discussion of this change in accounting principle, see Note T to the Consolidated Financial Statements.

[2] Goodwill in the Information Technology and Mission Systems reporting units is net of $536 and $1.3 billion of accumulated impairment losses, respectively.

[3] Includes adjustments during the purchase price allocation period.

[4] Consists primarily of adjustments for foreign currency translation and for the allocation of goodwill to operations classified as held for sale.

[5] Effective December 31, 2020, we reorganized our Information Technology and Mission Systems operating segments into a single Technologies segment. See Note A for additional information regarding the segment reorganization. This reorganization similarly changed the composition of our reporting units. Accordingly, goodwill of the Information Technology and Mission Systems reporting units was combined and assigned to the Technologies reporting unit.

[6] Goodwill in the Technologies reporting unit is net of $1.8 billion of accumulated impairment losses.