Quarterly Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	1 Months Ended	3 Months Ended									12 Months Ended
	Dec. 31, 2019	Jan. 04, 2020	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 30, 2017	Jan. 04, 2020	Dec. 29, 2018	Dec. 30, 2017
Summary of quarterly data
Total revenues		$ 4,035	$ 3,259	$ 3,227	$ 3,109	$ 3,750	$ 3,200	$ 3,726	$ 3,296		$ 13,630	$ 13,972	$ 14,198
Special charges		(72)				(73)					(72)	(73)	(130)
Gain on business disposition							444					444
Income tax benefit (expense)		(11)	(21)	(62)	(33)	(32)	(65)	(36)	(29)		(127)	(162)	(456)
Income from continuing operations		$ 199	$ 220	$ 217	$ 179	$ 246	$ 563	$ 224	$ 189		815	1,222	306
Net income											$ 815	$ 1,222	$ 307
Earnings per share from continuing operations
Basic earnings per share - continuing operations		$ 0.87	$ 0.96	$ 0.94	$ 0.76	$ 1.02	$ 2.29	$ 0.88	$ 0.73		$ 3.52	$ 4.88	$ 1.15
Diluted earnings per share - continuing operations		$ 0.87	$ 0.95	$ 0.93	$ 0.76	$ 1.02	$ 2.26	$ 0.87	$ 0.72		$ 3.50	$ 4.83	$ 1.14
Basic average shares outstanding		228,653	229,755	232,013	234,839	240,248	246,136	253,904	260,497		231,315	250,196	266,380
Basic average shares outstanding		229,790	231,097	233,545	236,437	242,569	249,378	257,177	263,672		232,709	253,237	268,750
Segment profit margins
Segment profit margin (as a percent)		8.40%	9.10%	10.50%	9.50%	10.60%	7.70%	9.30%	8.50%
Income tax expense charge to reflect provisional estimate of the net impact of Tax Cuts and Jobs Act										$ 266
Income tax benefit											$ 14
Disposition of businesses | Tools and Test Equipment
Summary of quarterly data
After tax gain		$ 419										$ 419
2018 Restructuring Plan
Summary of quarterly data
Special charges						$ (73)
2019 Restructuring Plan
Summary of quarterly data
Special charges	$ (72)
Arctic Cat Acquisition
Summary of quarterly data
Special charges													$ (130)
Operating Segment
Summary of quarterly data
Segment Profit		340	$ 297	$ 339	$ 294	397	$ 245	$ 346	$ 279		1,270	1,267	1,169
Corporate
Summary of quarterly data
Corporate expenses and other, net		(22)	(17)	(24)	(47)	(12)	(29)	(51)	(27)		(110)	(119)	(132)
Manufacturing group
Summary of quarterly data
Income from continuing operations											793	1,198	247
Manufacturing group | Reconciling Items
Summary of quarterly data
Interest expense, net for Manufacturing group		(36)	(39)	(36)	(35)	(34)	(32)	(35)	(34)		(146)	(135)	(145)
Textron Aviation
Summary of quarterly data
Special charges											(29)		(28)
Textron Aviation | Manufacturing group
Summary of quarterly data
Total revenues		$ 1,729	$ 1,201	$ 1,123	$ 1,134	$ 1,552	$ 1,133	$ 1,276	$ 1,010		5,187	4,971	4,686
Segment profit margins
Segment profit margin (as a percent)		7.80%	8.70%	9.40%	9.30%	11.00%	8.70%	8.20%	7.10%
Textron Aviation | Manufacturing group | Operating Segment
Summary of quarterly data
Segment Profit		$ 134	$ 104	$ 105	$ 106	$ 170	$ 99	$ 104	$ 72		449	445	303
Bell
Summary of quarterly data
Special charges													(23)
Bell | Manufacturing group
Summary of quarterly data
Total revenues		$ 961	$ 783	$ 771	$ 739	$ 827	$ 770	$ 831	$ 752		3,254	3,180	3,317
Segment profit margins
Segment profit margin (as a percent)		12.30%	14.00%	13.40%	14.10%	13.10%	14.70%	14.10%	11.60%
Bell | Manufacturing group | Operating Segment
Summary of quarterly data
Segment Profit		$ 118	$ 110	$ 103	$ 104	$ 108	$ 113	$ 117	$ 87		435	425	415
Textron Systems
Summary of quarterly data
Special charges													(21)
Textron Systems | Manufacturing group
Summary of quarterly data
Total revenues		$ 399	$ 311	$ 308	$ 307	$ 345	$ 352	$ 380	$ 387		1,325	1,464	1,840
Segment profit margins
Segment profit margin (as a percent)		8.30%	10.00%	15.90%	9.10%	10.70%	8.20%	10.50%	12.90%
Textron Systems | Manufacturing group | Operating Segment
Summary of quarterly data
Segment Profit		$ 33	$ 31	$ 49	$ 28	$ 37	$ 29	$ 40	$ 50		141	156	139
Industrial
Summary of quarterly data
Special charges											(38)	(73)	(58)
Industrial | Manufacturing group
Summary of quarterly data
Total revenues		$ 927	$ 950	$ 1,009	$ 912	$ 1,008	$ 930	$ 1,222	$ 1,131		3,798	4,291	4,286
Segment profit margins
Segment profit margin (as a percent)		4.70%	4.90%	7.50%	5.50%	7.20%	0.10%	6.50%	5.70%
Industrial | Manufacturing group | Operating Segment
Summary of quarterly data
Segment Profit		$ 44	$ 47	$ 76	$ 50	$ 73	$ 1	$ 80	$ 64		217	218	290
Industrial | Specialized vehicles | 2018 Restructuring Plan
Summary of quarterly data
Special charges						(73)
Industrial and Textron Aviation | 2019 Restructuring Plan
Summary of quarterly data
Special charges		72
Finance
Summary of quarterly data
Finance Revenue		$ 19	$ 14	$ 16	$ 17	$ 18	$ 15	$ 17	$ 16		66	66	69
Segment profit margins
Segment profit margin (as a percent)		57.90%	35.70%	37.50%	35.30%	50.00%	20.00%	29.40%	37.50%
Finance | Operating Segment
Summary of quarterly data
Segment Profit		$ 11	$ 5	$ 6	$ 6	$ 9	$ 3	$ 5	$ 6		$ 28	$ 23	$ 22