SHARE-BASED COMPENSATION - Narrative (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Apr. 03, 2026	Mar. 28, 2025
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based payment arrangement, expense	$ 21	$ 19
L3Harris Shareholder-approved Employee Stock Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued, net of shares withheld for tax purposes (in shares)	0.4	0.2