GOODWILL (Details)		6 Months Ended	9 Months Ended	12 Months Ended
	Jun. 29, 2019 USD ($)	Jan. 03, 2020 USD ($)	Oct. 02, 2020 USD ($) divestiture	Jan. 01, 2021 USD ($) divestiture
Goodwill [Roll Forward]
Beginning Balance	$ 5,340,000,000	$ 5,340,000,000	$ 20,001,000,000	$ 20,001,000,000
Goodwill acquired		14,649,000,000
Currency translation adjustments		12,000,000	(14,000,000)
Goodwill decrease from divestitures			(541,000,000)
Impairment of goodwill	0		(480,000,000)
Other (including adjustments to previously estimated fair value of assets acquire and liabilities assumed)			$ (90,000,000)
Ending Balance		20,001,000,000		$ 18,876,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Goodwill [Roll Forward]
Number of business divested | divestiture				3
Applied Kilovolts And Analytical Instrumentation, Airport Security And Automation And EOTech Businesses | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Goodwill [Roll Forward]
Goodwill decrease from divestitures				$ (541,000,000)
Number of business divested | divestiture			3
Integrated Mission Systems
Goodwill [Roll Forward]
Beginning Balance	64,000,000	64,000,000	$ 5,768,000,000	5,768,000,000
Goodwill acquired		5,704,000,000
Currency translation adjustments		1,000,000	(10,000,000)
Goodwill decrease from divestitures			0
Impairment of goodwill			0
Other (including adjustments to previously estimated fair value of assets acquire and liabilities assumed)			741,000,000
Ending Balance		5,768,000,000		6,499,000,000
Space and Airborne Systems
Goodwill [Roll Forward]
Beginning Balance	3,737,000,000	3,737,000,000	5,131,000,000	5,131,000,000
Goodwill acquired		1,390,000,000
Currency translation adjustments		4,000,000	(4,000,000)
Goodwill decrease from divestitures			(2,000,000)
Impairment of goodwill			(5,000,000)
Other (including adjustments to previously estimated fair value of assets acquire and liabilities assumed)			112,000,000
Ending Balance		5,131,000,000		5,232,000,000
Communication Systems
Goodwill [Roll Forward]
Beginning Balance	927,000,000	927,000,000	4,243,000,000	4,243,000,000
Goodwill acquired		3,316,000,000
Currency translation adjustments		0	1,000,000
Goodwill decrease from divestitures			(9,000,000)
Impairment of goodwill			0
Other (including adjustments to previously estimated fair value of assets acquire and liabilities assumed)			(82,000,000)
Ending Balance		4,243,000,000		4,153,000,000
Aviation Systems
Goodwill [Roll Forward]
Beginning Balance	$ 612,000,000	612,000,000	4,859,000,000	4,859,000,000
Goodwill acquired		4,239,000,000
Currency translation adjustments		7,000,000	(1,000,000)
Goodwill decrease from divestitures			(530,000,000)
Impairment of goodwill			(475,000,000)
Other (including adjustments to previously estimated fair value of assets acquire and liabilities assumed)			$ (861,000,000)
Ending Balance		$ 4,859,000,000		$ 2,992,000,000