Information on Business Segments - Total Assets and Customer Advances and Amounts In Excess Of Costs Incurred For Each Business Segment (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Assets	$ 50,710	$ 47,528
Operating Segments
Segment Reporting Information [Line Items]
Assets	39,355	38,734
Operating Segments | Aeronautics
Segment Reporting Information [Line Items]
Assets	9,903	9,109
Operating Segments | Missiles and Fire Control
Segment Reporting Information [Line Items]
Assets	4,966	5,030
Operating Segments | Rotary and Mission Systems
Segment Reporting Information [Line Items]
Assets	18,035	18,751
Operating Segments | Space
Segment Reporting Information [Line Items]
Assets	6,451	5,844
Corporate activities
Segment Reporting Information [Line Items]
Assets	$ 11,355	$ 8,794