BUSINESS SEGMENTS - Total Assets by Segment (Details) - USD ($) $ in Millions	Jan. 01, 2021	Jan. 03, 2020
Segment Reporting Information [Line Items]
Assets	$ 36,960	$ 38,336
Other intangible assets	7,908	8,458
Operating segments | Integrated Mission Systems
Segment Reporting Information [Line Items]
Assets	8,906	7,888
Operating segments | Space and Airborne Systems
Segment Reporting Information [Line Items]
Assets	6,943	6,837
Operating segments | Communication Systems
Segment Reporting Information [Line Items]
Assets	5,746	5,930
Operating segments | Aviation Systems
Segment Reporting Information [Line Items]
Assets	5,026	7,569
Corporate eliminations
Segment Reporting Information [Line Items]
Assets	10,339	10,112
Corporate eliminations | Exelis
Segment Reporting Information [Line Items]
Other intangible assets	$ 7,900	$ 8,500