BUSINESS SEGMENTS - Geographic Information (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jan. 03, 2020	Dec. 28, 2018	Jan. 01, 2021	Jan. 03, 2020	Jun. 28, 2019	Jun. 29, 2018
Segment Reporting Information [Line Items]
Capital Expenditures	$ 173		$ 368		$ 161	$ 136
Depreciation and Amortization	442		1,032		258	259
Revenue	9,263	$ 3,208	18,194	$ 12,856	6,801	6,168
U.S. operations
Segment Reporting Information [Line Items]
Revenue	8,485		16,998		6,530	5,854
Long-lived assets	1,865		1,949	1,865	866	892
International operations
Segment Reporting Information [Line Items]
Revenue	778		1,196		271	314
Long-lived assets	252		153	$ 252	28	8
Operating segments | Integrated Mission Systems
Segment Reporting Information [Line Items]
Capital Expenditures	29		67		1	1
Depreciation and Amortization	37		70		2	2
Revenue	2,758		5,538		52	55
Operating segments | Space and Airborne Systems
Segment Reporting Information [Line Items]
Capital Expenditures	36		92		48	49
Depreciation and Amortization	31		66		50	54
Revenue	2,377		4,946		3,711	3,294
Operating segments | Communication Systems
Segment Reporting Information [Line Items]
Capital Expenditures	22		58		29	25
Depreciation and Amortization	32		61		49	54
Revenue	2,151		4,443		2,208	2,015
Operating segments | Aviation Systems
Segment Reporting Information [Line Items]
Capital Expenditures	64		87		54	37
Depreciation and Amortization	53		103		29	22
Revenue	2,038		3,448		672	668
Operating segments | Other non-reportable business segments
Segment Reporting Information [Line Items]
Capital Expenditures	0		0		6	4
Depreciation and Amortization	0		0		3	5
Revenue	23		0		165	148
Corporate eliminations
Segment Reporting Information [Line Items]
Capital Expenditures	22		64		23	20
Depreciation and Amortization	$ 289		$ 732		$ 125	$ 122