Revenues - Disaggregation of Revenues (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jan. 02, 2021	Oct. 03, 2020	Jul. 04, 2020	Apr. 04, 2020	Jan. 04, 2020	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Jan. 02, 2021	Jan. 04, 2020	Dec. 29, 2018
Revenues
Revenues	$ 3,667	$ 2,735	$ 2,472	$ 2,777	$ 4,035	$ 3,259	$ 3,227	$ 3,109	$ 11,651	$ 13,630	$ 13,972
United States
Revenues
Revenues									7,943	8,963	8,667
Europe
Revenues
Revenues									1,336	1,986	2,187
Asia and Australia
Revenues
Revenues									1,106	1,070	1,253
Other international
Revenues
Revenues									1,266	1,611	1,865
Commercial
Revenues
Revenues									8,202	10,394	10,622
U.S. Government
Revenues
Revenues									3,449	3,236	3,350
Textron Aviation
Revenues
Revenues									3,974	5,187	4,971
Textron Aviation | United States
Revenues
Revenues									2,825	3,708	3,379
Textron Aviation | Europe
Revenues
Revenues									356	678	612
Textron Aviation | Asia and Australia
Revenues
Revenues									379	244	336
Textron Aviation | Other international
Revenues
Revenues									414	557	644
Textron Aviation | Commercial
Revenues
Revenues									3,826	4,956	4,734
Textron Aviation | U.S. Government
Revenues
Revenues									148	231	237
Textron Aviation | Aircraft
Revenues
Revenues									2,714	3,592	3,435
Textron Aviation | Aftermarket parts and services
Revenues
Revenues									1,260	1,595	1,536
Bell
Revenues
Revenues									3,309	3,254	3,180
Bell | United States
Revenues
Revenues									2,564	2,440	2,186
Bell | Europe
Revenues
Revenues									148	142	162
Bell | Asia and Australia
Revenues
Revenues									330	348	427
Bell | Other international
Revenues
Revenues									267	324	405
Bell | Commercial
Revenues
Revenues									1,079	1,238	1,114
Bell | U.S. Government
Revenues
Revenues									2,230	2,016	2,066
Bell | Military aircraft and support programs
Revenues
Revenues									2,213	1,988	2,030
Bell | Commercial helicopters, parts and services
Revenues
Revenues									1,096	1,266	1,150
Textron Systems
Revenues
Revenues									1,313	1,325	1,464
Textron Systems | United States
Revenues
Revenues									1,129	1,083	1,118
Textron Systems | Europe
Revenues
Revenues									44	73	74
Textron Systems | Asia and Australia
Revenues
Revenues									67	103	127
Textron Systems | Other international
Revenues
Revenues									73	66	145
Textron Systems | Commercial
Revenues
Revenues									249	359	431
Textron Systems | U.S. Government
Revenues
Revenues									1,064	966	1,033
Textron Systems | Unmanned systems
Revenues
Revenues									621	572	612
Textron Systems | Marine and land systems
Revenues
Revenues									179	208	311
Textron Systems | Simulation, training and other
Revenues
Revenues									513	545	541
Industrial
Revenues
Revenues									3,000	3,798	4,291
Industrial | United States
Revenues
Revenues									1,398	1,698	1,957
Industrial | Europe
Revenues
Revenues									786	1,091	1,333
Industrial | Asia and Australia
Revenues
Revenues									328	374	357
Industrial | Other international
Revenues
Revenues									488	635	644
Industrial | Commercial
Revenues
Revenues									2,993	3,775	4,277
Industrial | U.S. Government
Revenues
Revenues									7	23	14
Industrial | Fuel systems and functional components
Revenues
Revenues									1,751	2,237	2,352
Industrial | Specialized vehicles
Revenues
Revenues									1,249	1,561	1,691
Industrial | Tools and test equipment
Revenues
Revenues									0	0	248
Finance
Revenues
Revenues									55	66	66
Finance | United States
Revenues
Revenues									27	34	27
Finance | Europe
Revenues
Revenues									2	2	6
Finance | Asia and Australia
Revenues
Revenues									2	1	6
Finance | Other international
Revenues
Revenues									24	29	27
Finance | Commercial
Revenues
Revenues									55	66	66
Finance | U.S. Government
Revenues
Revenues									$ 0	$ 0	$ 0