Segment Information Sales by Customer Type (Details 2) - 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, Major Customer [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%
US Government
Revenue, Major Customer [Line Items]
Sales										$ 30,903	$ 27,934	$ 24,796
Concentration Risk, Percentage										84.00%	83.00%	82.00%
US Government | Aeronautics Systems
Revenue, Major Customer [Line Items]
Sales										$ 10,411	$ 9,258	$ 8,732
Concentration Risk, Percentage										86.00%	83.00%	85.00%
US Government | Defense Systems
Revenue, Major Customer [Line Items]
Sales										$ 5,103	$ 4,952	$ 4,132
Concentration Risk, Percentage										68.00%	66.00%	62.00%
US Government | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales										$ 7,279	$ 6,765	$ 6,501
Concentration Risk, Percentage										72.00%	72.00%	73.00%
US Government | Space Systems
Revenue, Major Customer [Line Items]
Sales										$ 8,110	$ 6,959	$ 5,431
Concentration Risk, Percentage										93.00%	94.00%	93.00%
International
Revenue, Major Customer [Line Items]
Sales										$ 5,188	$ 5,154	$ 4,434
Concentration Risk, Percentage										14.00%	15.00%	15.00%
International | Aeronautics Systems
Revenue, Major Customer [Line Items]
Sales										$ 1,595	$ 1,688	$ 1,402
Concentration Risk, Percentage										13.00%	15.00%	13.00%
International | Defense Systems
Revenue, Major Customer [Line Items]
Sales										$ 1,317	$ 1,442	$ 1,249
Concentration Risk, Percentage										17.00%	19.00%	19.00%
International | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales										$ 1,945	$ 1,839	$ 1,653
Concentration Risk, Percentage										19.00%	19.00%	18.00%
International | Space Systems
Revenue, Major Customer [Line Items]
Sales										$ 331	$ 185	$ 130
Concentration Risk, Percentage										4.00%	2.00%	2.00%
Other Customers
Revenue, Major Customer [Line Items]
Sales										$ 708	$ 753	$ 865
Concentration Risk, Percentage										2.00%	2.00%	3.00%
Other Customers | Aeronautics Systems
Revenue, Major Customer [Line Items]
Sales										$ 41	$ 67	$ 86
Concentration Risk, Percentage										0.00%	1.00%	1.00%
Other Customers | Defense Systems
Revenue, Major Customer [Line Items]
Sales										$ 395	$ 410	$ 481
Concentration Risk, Percentage										5.00%	6.00%	7.00%
Other Customers | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales										$ 77	$ 78	$ 77
Concentration Risk, Percentage										1.00%	1.00%	1.00%
Other Customers | Space Systems
Revenue, Major Customer [Line Items]
Sales										$ 195	$ 198	$ 221
Concentration Risk, Percentage										2.00%	3.00%	4.00%
Intersegment Sales [Member] | Aeronautics Systems
Revenue, Major Customer [Line Items]
Sales										$ 122	$ 103	$ 73
Concentration Risk, Percentage										1.00%	1.00%	1.00%
Intersegment Sales [Member] | Defense Systems
Revenue, Major Customer [Line Items]
Sales										$ 728	$ 691	$ 750
Concentration Risk, Percentage										10.00%	9.00%	12.00%
Intersegment Sales [Member] | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales										$ 779	$ 728	$ 718
Concentration Risk, Percentage										8.00%	8.00%	8.00%
Intersegment Sales [Member] | Space Systems
Revenue, Major Customer [Line Items]
Sales										$ 108	$ 83	$ 63
Concentration Risk, Percentage										1.00%	1.00%	1.00%
Operating Segments [Member] | Aeronautics Systems
Revenue, Major Customer [Line Items]
Sales										$ 12,169	$ 11,116	$ 10,293
Concentration Risk, Percentage										100.00%	100.00%	100.00%
Operating Segments [Member] | Defense Systems
Revenue, Major Customer [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, Major Customer [Line Items]
Sales										$ 10,080	$ 9,410	$ 8,949
Concentration Risk, Percentage										100.00%	100.00%	100.00%
Operating Segments [Member] | Space Systems
Revenue, Major Customer [Line Items]
Sales									$ 3,100	$ 8,744	$ 7,425	$ 5,845
Concentration Risk, Percentage										100.00%	100.00%	100.00%