Segment Information (Unaudited) Sales by Customer Type (Details 2) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue, Major Customer [Line Items]
Sales	$ 9,157	$ 8,620
Concentration Risk, Percentage	100.00%	100.00%
U.S. government(1)
Revenue, Major Customer [Line Items]
Sales	$ 7,694	$ 7,094
Concentration Risk, Percentage	84.00%	83.00%
U.S. government(1) | Aeronautics Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 2,541	$ 2,361
Concentration Risk, Percentage	85.00%	83.00%
U.S. government(1) | Defense Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 993	$ 1,259
Concentration Risk, Percentage	64.00%	67.00%
U.S. government(1) | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 1,834	$ 1,671
Concentration Risk, Percentage	71.00%	71.00%
U.S. government(1) | Space Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 2,326	$ 1,803
Concentration Risk, Percentage	92.00%	93.00%
International(2)
Revenue, Major Customer [Line Items]
Sales	$ 1,357	$ 1,335
Concentration Risk, Percentage	15.00%	15.00%
International(2) | Aeronautics Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 399	$ 444
Concentration Risk, Percentage	14.00%	16.00%
International(2) | Defense Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 351	$ 340
Concentration Risk, Percentage	22.00%	18.00%
International(2) | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 502	$ 483
Concentration Risk, Percentage	19.00%	21.00%
International(2) | Space Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 105	$ 68
Concentration Risk, Percentage	4.00%	3.00%
Other customers
Revenue, Major Customer [Line Items]
Sales	$ 106	$ 191
Concentration Risk, Percentage	1.00%	2.00%
Other customers | Aeronautics Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 6	$ 12
Concentration Risk, Percentage	0.00%	0.00%
Other customers | Defense Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 33	$ 111
Concentration Risk, Percentage	2.00%	6.00%
Other customers | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 16	$ 17
Concentration Risk, Percentage	1.00%	1.00%
Other customers | Space Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 51	$ 51
Concentration Risk, Percentage	2.00%	3.00%
Intersegment Sales [Member] | Aeronautics Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 44	$ 26
Concentration Risk, Percentage	1.00%	1.00%
Intersegment Sales [Member] | Defense Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 185	$ 171
Concentration Risk, Percentage	12.00%	9.00%
Intersegment Sales [Member] | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 237	$ 176
Concentration Risk, Percentage	9.00%	7.00%
Intersegment Sales [Member] | Space Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 39	$ 26
Concentration Risk, Percentage	2.00%	1.00%
Operating Segments [Member] | Aeronautics Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 2,990	$ 2,843
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Defense Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 1,562	$ 1,881
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 2,589	$ 2,347
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Space Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 2,521	$ 1,948
Concentration Risk, Percentage	100.00%	100.00%