RESTRUCTURING COSTS - Narrative (Details) $ in Millions	12 Months Ended
	Sep. 30, 2025 USD ($) position facilty	Sep. 30, 2024 USD ($) facilty position	Sep. 30, 2023 USD ($) facilty position	Sep. 30, 2026 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 136	$ 228	$ 72
Number of positions eliminated | position	2,100	2,250	700
Total number of facilities exited | facilty	13	22	10
Costs incurred related to restructuring actions	$ 26	$ 16	$ 20
Corporate and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	41	$ 51	$ 14
Corporate and other | National Instruments
Restructuring Cost and Reserve [Line Items]
Restructuring costs	3
Corporate and other | AspenTech
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 22
Forecast
Restructuring Cost and Reserve [Line Items]
Restructuring costs, expected future cost				$ 100