BUSINESS SEGMENTS Revenue and Income by Segments (Details) - USD ($) $ in Millions	12 Months Ended
Jun. 28, 2019	Jun. 29, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 6,801	$ 6,168	$ 5,897
Non-operating income	188	156	166
Income from continuing operations before income taxes	1,113	908	889
Amortization expense related to intangible assets	115	117	126
Exelis
Segment Reporting Information [Line Items]
Amortization expense related to intangible assets	101	101	109
Communication Systems
Segment Reporting Information [Line Items]
Revenue	2,177	1,904	1,754
Electronic Systems
Segment Reporting Information [Line Items]
Revenue	2,583	2,365	2,245
Space and Intelligence Systems
Segment Reporting Information [Line Items]
Revenue	2,057	1,913	1,904
Operating Segments \| Communication Systems
Segment Reporting Information [Line Items]
Revenue	2,177	1,904	1,754
Segment operating income (loss)	654	566	514
Operating Segments \| Electronic Systems
Segment Reporting Information [Line Items]
Revenue	2,583	2,365	2,245
Segment operating income (loss)	499	432	457
Operating Segments \| Space and Intelligence Systems
Segment Reporting Information [Line Items]
Revenue	2,057	1,913	1,904
Segment operating income (loss)	359	331	314
Corporate eliminations
Segment Reporting Information [Line Items]
Revenue	(16)	(14)	(6)
Unallocated corporate expense and corporate eliminations
Segment Reporting Information [Line Items]
Segment operating income (loss)	(234)	(225)	(228)
Non-cash adjustment for deferred compensation		12
Unallocated corporate expense and corporate eliminations \| L3
Segment Reporting Information [Line Items]
Merger-related transactions and integration costs	65
Unallocated corporate expense and corporate eliminations \| Exelis
Segment Reporting Information [Line Items]
Merger-related transactions and integration costs		5	58
Amortization expense related to intangible assets	101	101	109
Unallocated corporate expense and corporate eliminations \| Business Exit \| Commercial Line Business
Segment Reporting Information [Line Items]
Business charges in connection with transition and exit costs		47
Segment Reconciling Items
Segment Reporting Information [Line Items]
Segment operating income (loss)		(27)
Pension adjustment	(186)	(184)	(164)
Non-operating income	188	156	166
Net interest expense	$ (167)	$ (168)	$ (170)

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