BUSINESS SEGMENTS - Depreciation & Amortization (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Depreciation and amortization	$ 384	$ 424	$ 767	$ 846
National Instruments
Segment Reporting Information [Line Items]
Amortization of intangible assets		34		68
Operating Segments | Intelligent Devices
Segment Reporting Information [Line Items]
Depreciation and amortization	108	108	215	224
Operating Segments | Software and Control
Segment Reporting Information [Line Items]
Depreciation and amortization	265	305	530	600
Operating Segments | Final Control | Intelligent Devices
Segment Reporting Information [Line Items]
Depreciation and amortization	41	39	81	79
Operating Segments | Measurement & Analytical | Intelligent Devices
Segment Reporting Information [Line Items]
Depreciation and amortization	31	33	62	73
Operating Segments | Discrete Automation | Intelligent Devices
Segment Reporting Information [Line Items]
Depreciation and amortization	22	21	43	43
Operating Segments | Safety & Productivity | Intelligent Devices
Segment Reporting Information [Line Items]
Depreciation and amortization	14	15	29	29
Operating Segments | Control Systems & Software | Software and Control
Segment Reporting Information [Line Items]
Depreciation and amortization	146	152	293	296
Operating Segments | Test & Measurement | Software and Control
Segment Reporting Information [Line Items]
Depreciation and amortization	119	153	237	304
Corporate and other
Segment Reporting Information [Line Items]
Depreciation and amortization	$ 11	$ 11	$ 22	$ 22