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, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Assets	$ 46,521	$ 47,806
Customer advances and amounts in excess of costs incurred	6,752	6,776
Aeronautics
Segment Reporting Information [Line Items]
Customer advances and amounts in excess of costs incurred	2,752	2,133
Missiles and Fire Control
Segment Reporting Information [Line Items]
Customer advances and amounts in excess of costs incurred	1,268	1,517
Rotary and Mission Systems
Segment Reporting Information [Line Items]
Customer advances and amounts in excess of costs incurred	2,288	2,590
Space
Segment Reporting Information [Line Items]
Customer advances and amounts in excess of costs incurred	444	536
Operating Segments
Segment Reporting Information [Line Items]
Assets	35,769	35,513
Operating Segments | Aeronautics
Segment Reporting Information [Line Items]
Assets	7,903	7,896
Operating Segments | Missiles and Fire Control
Segment Reporting Information [Line Items]
Assets	4,395	4,000
Operating Segments | Rotary and Mission Systems
Segment Reporting Information [Line Items]
Assets	18,235	18,367
Operating Segments | Space
Segment Reporting Information [Line Items]
Assets	5,236	5,250
Corporate activities
Segment Reporting Information [Line Items]
Assets	$ 10,752	$ 12,293