LONG-TERM DEBT- Narrative (Details) € in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Mar. 31, 2025 USD ($)	Mar. 31, 2025 EUR (€)	Sep. 30, 2019 EUR (€)
Debt Instrument [Line Items]
Long-term debt, maturing in 2026	$ 757
Long-term debt, maturing in 2027	528
Long-term debt, maturing in 2028	997
Long-term debt, maturing in 2029	584
Interest paid on long-term debt	221	$ 193	$ 200
Repayments of long-term debt	503	547	$ 741
Senior Notes
Debt Instrument [Line Items]
Debt, face amount | €						€ 1,500
3.15% notes due June 2025 | Notes Payable
Debt Instrument [Line Items]
Repayments of long-term debt	$ 500
Notes interest rate, percentage	3.15%
Three Point Zero Percentage Due Two Thousand Thirty One | Senior Notes
Debt Instrument [Line Items]
Notes interest rate, percentage				3.00%	3.00%
Debt, face amount | €					€ 500
Five Point Zero Percentage Due Two Thousand Thirty Five | Senior Notes
Debt Instrument [Line Items]
Notes interest rate, percentage				5.00%	5.00%
Debt, face amount				$ 500
Three Point Five Percentage Due Two Thousand Thirty Siven | Senior Notes
Debt Instrument [Line Items]
Notes interest rate, percentage				3.50%	3.50%
Debt, face amount | €					€ 500
0.375% euro notes due May 2024 | Notes Payable
Debt Instrument [Line Items]
Repayments of long-term debt		$ 529
Notes interest rate, percentage		0.375%