Business Segment Information - Total Assets by Segment (Details) - USD ($) $ in Millions	Oct. 02, 2020	Jan. 03, 2020
Segment Reporting Information [Line Items]
Assets	$ 37,145	$ 38,336
Identifiable intangibles assets acquired	8,172	8,458
Operating segments | Integrated Mission Systems
Segment Reporting Information [Line Items]
Assets	8,752	7,888
Operating segments | Space and Airborne Systems
Segment Reporting Information [Line Items]
Assets	6,902	6,837
Operating segments | Communication Systems
Segment Reporting Information [Line Items]
Assets	5,643	5,930
Operating segments | Aviation Systems
Segment Reporting Information [Line Items]
Assets	5,231	7,569
Corporate
Segment Reporting Information [Line Items]
Assets	10,617	10,112
Corporate | Exelis
Segment Reporting Information [Line Items]
Identifiable intangibles assets acquired	$ 8,200	$ 8,500