TRANSITION PERIOD COMPARATIVE DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	6 Months Ended		12 Months Ended
	Jan. 03, 2020	Dec. 28, 2018	Dec. 31, 2021	Jan. 01, 2021	Jan. 03, 2020	Jun. 28, 2019
Condensed Financial Information Disclosure [Abstract]
Revenue from product sales and services	$ 9,263	$ 3,208	$ 17,814	$ 18,194	$ 12,856	$ 6,801
Cost of product sales and services	(6,726)	(2,105)	(12,438)	(12,886)	(9,088)	(4,467)
Engineering, selling and administrative expenses	(1,881)	(583)	(3,280)	(3,315)	(2,540)	(1,242)
Business divestiture-related gains (losses)	229	0	220	(51)	229	0
Impairment of goodwill and other assets	(46)	0	(207)	(767)	(46)	0
Non-operating income	192	94	439	401	286	188
Net interest expense	(123)	(86)	(265)	(254)	(204)	(167)
Income from continuing operations before income taxes	908	528	2,283	1,322	1,493	1,113
Income taxes	(73)	(87)	(440)	(234)	(146)	(160)
Income from continuing operations	835	441	1,843	1,088	1,347	953
Discontinued operations, net of income taxes	(1)	(3)	(1)	(2)	(2)	(4)
Net income	834	438	1,842	1,086	1,345	949
Noncontrolling interests, net of income taxes	(12)	0	4	33	(12)	0
Net income attributable to L3Harris Technologies, Inc.	$ 822	$ 438	$ 1,846	$ 1,119	$ 1,333	$ 949
Basic
Continuing operations (in dollars per share)	$ 3.72	$ 3.74	$ 9.17	$ 5.24	$ 8.04	$ 8.06
Discontinued operations (in dollars per share)	0	(0.03)	0	(0.01)	0	(0.03)
Total basic net income per common share (in dollars per share)	3.72	3.71	9.17	5.23	8.04	8.03
Diluted
Continuing operations (in dollars per share)	3.68	3.66	9.09	5.19	7.90	7.89
Discontinued operations (in dollars per share)	(0.01)	(0.02)	0	0	(0.01)	(0.03)
Diluted (in dollars per share)	$ 3.67	$ 3.64	$ 9.09	$ 5.19	$ 7.89	$ 7.86
Basic weighted average common shares outstanding (in shares)	221.2	117.8	201.3	214.0	166.0	118.0
Diluted weighted average common shares outstanding (in shares)	223.7	120.3	203.2	215.9	169.0	120.5