BUSINESS SEGMENTS - Geographic Information (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jan. 03, 2020	Dec. 28, 2018	Jun. 28, 2019	Jun. 29, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Capital Expenditures	$ 173		$ 161	$ 136	$ 119
Depreciation and Amortization	442		258	259	311
Revenue	9,263	$ 3,208	6,801	6,168	5,897
U.S. operations
Segment Reporting Information [Line Items]
Revenue	8,485		6,530	5,854	5,637
Long-lived assets	1,865		866	892	896
International Operations
Segment Reporting Information [Line Items]
Revenue	778		271	314	260
Long-lived assets	252		28	8	8
Discontinued Operations
Segment Reporting Information [Line Items]
Capital Expenditures	0		0	0	4
Depreciation and Amortization	0		0	0	39
Integrated Mission Systems
Segment Reporting Information [Line Items]
Revenue	2,774		48	45	38
Integrated Mission Systems | U.S. operations
Segment Reporting Information [Line Items]
Revenue	2,300		30	39	27
Integrated Mission Systems | International Operations
Segment Reporting Information [Line Items]
Revenue	474		18	6	11
Communication Systems
Segment Reporting Information [Line Items]
Revenue	2,151		2,208	2,015	1,891
Communication Systems | U.S. operations
Segment Reporting Information [Line Items]
Revenue	1,518		1,281	1,031	880
Communication Systems | International Operations
Segment Reporting Information [Line Items]
Revenue	633		927	984	1,011
Aviation Systems
Segment Reporting Information [Line Items]
Revenue	2,038		672	668	697
Aviation Systems | U.S. operations
Segment Reporting Information [Line Items]
Revenue	1,514		644	627	647
Aviation Systems | International Operations
Segment Reporting Information [Line Items]
Revenue	524		28	41	50
Other non-reportable business segments
Segment Reporting Information [Line Items]
Revenue	23		165	148	121
Operating segments | Integrated Mission Systems
Segment Reporting Information [Line Items]
Revenue	2,774		48	45	38
Operating segments | Integrated Mission Systems | Continuing Operations
Segment Reporting Information [Line Items]
Capital Expenditures	29		1	1	0
Depreciation and Amortization	37		2	2	2
Operating segments | Space and Airborne Systems
Segment Reporting Information [Line Items]
Revenue	2,360		3,715	3,304	3,156
Operating segments | Space and Airborne Systems | Continuing Operations
Segment Reporting Information [Line Items]
Capital Expenditures	36		48	49	49
Depreciation and Amortization	31		50	54	55
Operating segments | Communication Systems
Segment Reporting Information [Line Items]
Revenue	2,151		2,208	2,015	1,891
Operating segments | Communication Systems | Continuing Operations
Segment Reporting Information [Line Items]
Capital Expenditures	22		29	25	16
Depreciation and Amortization	32		49	54	60
Operating segments | Aviation Systems
Segment Reporting Information [Line Items]
Revenue	2,038		672	668	697
Operating segments | Aviation Systems | Continuing Operations
Segment Reporting Information [Line Items]
Capital Expenditures	64		54	37	22
Depreciation and Amortization	53		29	22	5
Operating segments | Other non-reportable business segments | Continuing Operations
Segment Reporting Information [Line Items]
Capital Expenditures	0		6	4	1
Depreciation and Amortization	0		3	5	8
Corporate eliminations
Segment Reporting Information [Line Items]
Revenue	(83)		(7)	(12)	(6)
Corporate eliminations | Continuing Operations
Segment Reporting Information [Line Items]
Capital Expenditures	22		23	20	27
Depreciation and Amortization	$ 289		$ 125	$ 122	$ 142