Segment Information Sales by Geographic Location (Details 4) - 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
Revenues from External Customers and Long-Lived Assets [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%
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 31,611	$ 28,687	$ 25,661
Concentration Risk, Percentage										86.00%	85.00%	85.00%
Asia/Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 1,968	$ 1,836	$ 1,666
Concentration Risk, Percentage										5.00%	6.00%	6.00%
All Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 1,138	$ 1,485	$ 1,254
Concentration Risk, Percentage										3.00%	4.00%	4.00%
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 2,082	$ 1,833	$ 1,514
Concentration Risk, Percentage										6.00%	5.00%	5.00%
Aeronautics Systems | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 10,452	$ 9,325	$ 8,818
Concentration Risk, Percentage										87.00%	85.00%	86.00%
Aeronautics Systems | Asia/Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 841	$ 810	$ 677
Concentration Risk, Percentage										7.00%	7.00%	7.00%
Aeronautics Systems | All Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 180	$ 291	$ 189
Concentration Risk, Percentage										1.00%	3.00%	2.00%
Aeronautics Systems | Intersegment Sales [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 122	$ 103	$ 73
Aeronautics Systems | Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 574	$ 587	$ 536
Concentration Risk, Percentage										5.00%	5.00%	5.00%
Aeronautics Systems | Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 12,169	$ 11,116	$ 10,293
Concentration Risk, Percentage										100.00%	100.00%	100.00%
Defense Systems | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 5,498	$ 5,362	$ 4,613
Concentration Risk, Percentage										81.00%	79.00%	79.00%
Defense Systems | Asia/Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 402	$ 369	$ 365
Concentration Risk, Percentage										6.00%	5.00%	6.00%
Defense Systems | All Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 600	$ 824	$ 680
Concentration Risk, Percentage										9.00%	12.00%	12.00%
Defense Systems | Intersegment Sales [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 728	$ 691	$ 750
Defense Systems | Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 315	$ 249	$ 204
Concentration Risk, Percentage										4.00%	4.00%	3.00%
Defense Systems | Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 7,543	$ 7,495	$ 6,612
Concentration Risk, Percentage										100.00%	100.00%	100.00%
Mission Systems [Member] | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 7,356	$ 6,843	$ 6,578
Concentration Risk, Percentage										79.00%	79.00%	80.00%
Mission Systems [Member] | Asia/Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 707	$ 637	$ 592
Concentration Risk, Percentage										8.00%	7.00%	7.00%
Mission Systems [Member] | All Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 345	$ 352	$ 379
Concentration Risk, Percentage										4.00%	4.00%	5.00%
Mission Systems [Member] | Intersegment Sales [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 779	$ 728	$ 718
Mission Systems [Member] | Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 893	$ 850	$ 682
Concentration Risk, Percentage										9.00%	10.00%	8.00%
Mission Systems [Member] | Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 10,080	$ 9,410	$ 8,949
Concentration Risk, Percentage										100.00%	100.00%	100.00%
Space Systems | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 8,305	$ 7,157	$ 5,652
Concentration Risk, Percentage										96.00%	98.00%	98.00%
Space Systems | Asia/Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 18	$ 20	$ 32
Concentration Risk, Percentage										0.00%	0.00%	0.00%
Space Systems | All Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 13	$ 18	$ 6
Concentration Risk, Percentage										0.00%	0.00%	0.00%
Space Systems | Intersegment Sales [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 108	$ 83	$ 63
Space Systems | Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales										$ 300	$ 147	$ 92
Concentration Risk, Percentage										4.00%	2.00%	2.00%
Space Systems | Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales									$ 3,100	$ 8,744	$ 7,425	$ 5,845
Concentration Risk, Percentage										100.00%	100.00%	100.00%