Information on Business Segments - Total Assets and Customer Advances and Amounts In Excess Of Costs Incurred For Each Business Segment (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Assets	$ 47,528	$ 44,876
Operating Segments
Segment Reporting Information [Line Items]
Assets	38,734	37,230
Operating Segments | Aeronautics
Segment Reporting Information [Line Items]
Assets	9,109	8,435
Operating Segments | Missiles and Fire Control
Segment Reporting Information [Line Items]
Assets	5,030	5,017
Operating Segments | Rotary and Mission Systems
Segment Reporting Information [Line Items]
Assets	18,751	18,333
Operating Segments | Space
Segment Reporting Information [Line Items]
Assets	5,844	5,445
Corporate activities
Segment Reporting Information [Line Items]
Assets	$ 8,794	$ 7,646