Segment Financial Information - Capital Expenditures, Depreciation and Amortization and Assets by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 03, 2026	Sep. 27, 2025	Oct. 03, 2026	Sep. 27, 2025	Jan. 03, 2026
Other Information by Segment
Capital Expenditures	$ 102	$ 76	$ 330	$ 210
Depreciation and Amortization	101	97	291	289
Assets	18,346		18,346		$ 18,129
Manufacturing group
Other Information by Segment
Depreciation and Amortization			291	289
Assets	17,657		17,657		17,452
Manufacturing group \| Corporate
Other Information by Segment
Capital Expenditures	1	1	4	1
Depreciation and Amortization	1	2	5	5
Assets	4,324		4,324		4,688
Manufacturing group \| Textron Aviation \| Operating Segment
Other Information by Segment
Capital Expenditures	28	30	92	93
Depreciation and Amortization	45	43	125	124
Assets	5,113		5,113		5,103
Manufacturing group \| Bell \| Operating Segment
Other Information by Segment
Capital Expenditures	37	26	139	59
Depreciation and Amortization	26	23	74	73
Assets	3,596		3,596		3,132
Manufacturing group \| Textron Systems \| Operating Segment
Other Information by Segment
Capital Expenditures	13	7	35	20
Depreciation and Amortization	12	12	35	36
Assets	2,283		2,283		2,224
Manufacturing group \| Industrial \| Operating Segment
Other Information by Segment
Capital Expenditures	23	12	60	37
Depreciation and Amortization	17	$ 17	52	51
Assets	2,341		2,341		2,305
Finance group
Other Information by Segment
Depreciation and Amortization			0	$ 0
Assets	689		689		677
Finance group \| Finance \| Operating Segment
Other Information by Segment
Assets	$ 689		$ 689		$ 677