Segment Information Sales by Contract Type (Details 3) - USD ($) $ in Millions	3 Months Ended								7 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, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue, Contract Type [Line Items]
Sales	$ 10,212	$ 9,083	$ 8,884	$ 8,620	$ 8,721	$ 8,475	$ 8,456	$ 8,189		$ 36,799	$ 33,841	$ 30,095
Concentration Risk, Percentage										100.00%	100.00%	100.00%
Operating Segments [Member] | Aeronautics Systems
Revenue, Contract Type [Line Items]
Sales										$ 12,169	$ 11,116	$ 10,293
Concentration Risk, Percentage										100.00%	100.00%	100.00%
Operating Segments [Member] | Defense Systems
Revenue, Contract Type [Line Items]
Sales										$ 7,543	$ 7,495	$ 6,612
Concentration Risk, Percentage										100.00%	100.00%	100.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales										$ 10,080	$ 9,410	$ 8,949
Concentration Risk, Percentage										100.00%	100.00%	100.00%
Operating Segments [Member] | Space Systems
Revenue, Contract Type [Line Items]
Sales									$ 3,100	$ 8,744	$ 7,425	$ 5,845
Concentration Risk, Percentage										100.00%	100.00%	100.00%
Cost-type
Revenue, Contract Type [Line Items]
Sales										$ 18,438	$ 16,479	$ 15,004
Concentration Risk, Percentage										50.00%	49.00%	50.00%
Cost-type | Aeronautics Systems
Revenue, Contract Type [Line Items]
Sales										$ 6,142	$ 5,299	$ 5,066
Concentration Risk, Percentage										51.00%	48.00%	50.00%
Cost-type | Defense Systems
Revenue, Contract Type [Line Items]
Sales										$ 2,345	$ 2,509	$ 2,386
Concentration Risk, Percentage										34.00%	37.00%	41.00%
Cost-type | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales										$ 3,582	$ 3,335	$ 3,099
Concentration Risk, Percentage										39.00%	38.00%	38.00%
Cost-type | Space Systems
Revenue, Contract Type [Line Items]
Sales										$ 6,369	$ 5,336	$ 4,453
Concentration Risk, Percentage										74.00%	73.00%	77.00%
Fixed-price
Revenue, Contract Type [Line Items]
Sales										$ 18,361	$ 17,362	$ 15,091
Concentration Risk, Percentage										50.00%	51.00%	50.00%
Fixed-price | Aeronautics Systems
Revenue, Contract Type [Line Items]
Sales										$ 5,905	$ 5,714	$ 5,154
Concentration Risk, Percentage										49.00%	52.00%	50.00%
Fixed-price | Defense Systems
Revenue, Contract Type [Line Items]
Sales										$ 4,470	$ 4,295	$ 3,476
Concentration Risk, Percentage										66.00%	63.00%	59.00%
Fixed-price | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales										$ 5,719	$ 5,347	$ 5,132
Concentration Risk, Percentage										61.00%	62.00%	62.00%
Fixed-price | Space Systems
Revenue, Contract Type [Line Items]
Sales										$ 2,267	$ 2,006	$ 1,329
Concentration Risk, Percentage										26.00%	27.00%	23.00%
Intersegment Sales [Member] | Aeronautics Systems
Revenue, Contract Type [Line Items]
Sales										$ 122	$ 103	$ 73
Intersegment Sales [Member] | Defense Systems
Revenue, Contract Type [Line Items]
Sales										728	691	750
Intersegment Sales [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales										779	728	718
Intersegment Sales [Member] | Space Systems
Revenue, Contract Type [Line Items]
Sales										$ 108	$ 83	$ 63