Segment Financial Information - Capital Expenditures, Depreciation and Amortization and Assets by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 04, 2026	Jun. 28, 2025	Jul. 04, 2026	Jun. 28, 2025	Jan. 03, 2026
Other Information by Segment
Capital Expenditures	$ 95	$ 78	$ 228	$ 134
Depreciation and Amortization	94	100	190	192
Assets	18,134		18,134		$ 18,129
Manufacturing group
Other Information by Segment
Depreciation and Amortization			190	192
Assets	17,435		17,435		17,452
Manufacturing group \| Corporate
Other Information by Segment
Capital Expenditures	1	0	3	0
Depreciation and Amortization	2	1	4	3
Assets	4,139		4,139		4,688
Manufacturing group \| Textron Aviation \| Operating Segment
Other Information by Segment
Capital Expenditures	32	37	64	63
Depreciation and Amortization	39	42	80	81
Assets	5,214		5,214		5,103
Manufacturing group \| Bell \| Operating Segment
Other Information by Segment
Capital Expenditures	30	18	102	33
Depreciation and Amortization	24	28	48	50
Assets	3,445		3,445		3,132
Manufacturing group \| Textron Systems \| Operating Segment
Other Information by Segment
Capital Expenditures	16	8	22	13
Depreciation and Amortization	11	12	23	24
Assets	2,251		2,251		2,224
Manufacturing group \| Industrial \| Operating Segment
Other Information by Segment
Capital Expenditures	16	15	37	25
Depreciation and Amortization	18	$ 17	35	34
Assets	2,386		2,386		2,305
Finance group
Other Information by Segment
Depreciation and Amortization			0	$ 0
Assets	699		699		677
Finance group \| Finance \| Operating Segment
Other Information by Segment
Assets	$ 699		$ 699		$ 677