BUSINESS COMBINIATION - Additional Information (Details) $ / shares in Units, shares in Thousands, employee in Thousands, $ in Millions		6 Months Ended	12 Months Ended
	Jun. 29, 2019 employee $ / shares shares	Jan. 03, 2020 USD ($) employee	Dec. 31, 2018 USD ($)	Jun. 29, 2018 USD ($)
Business Acquisition [Line Items]
Number of employees | employee		50
Restructuring charges		$ 117		$ 51
Workforce reduction
Business Acquisition [Line Items]
Restructuring charges		117		$ 1
L3Harris
Business Acquisition [Line Items]
Exchange ratio	1.30
Shares issued for total merger consideration (in shares) | shares	104,100
Price per share of common stock (in dollars per share) | $ / shares	$ 189.13
Merger-related charges		532
Additional cost of sales related to fair value step-up in inventory sold		142
Restructuring charges		117
Transaction costs		83
Integration costs		72
Equity acceleration upon change in control		70
Facility consolidation costs		48
L3Harris | L3
Business Acquisition [Line Items]
Number of employees | employee	31
Revenue from product sales and services — pro forma			$ 10,000
Shares issued for total merger consideration (in shares) | shares	80,080
Net revenues from acquiree for the reporting period		5,700
Income from continuing operations before income taxes of acquiree for the reporting period		400
L3Harris | L3 | Workforce reduction
Business Acquisition [Line Items]
Restructuring charges		$ 108
L3Harris | Former Harris Shareholders
Business Acquisition [Line Items]
Percentage of voting interests acquired	54.00%
L3Harris | Former L3 Shareholders
Business Acquisition [Line Items]
Percentage of voting interests acquired	46.00%