Debt and Financing Arrangements (Details) - USD ($)	Dec. 31, 2023	Sep. 30, 2023
Short-Term Debt [Line Items]
Short-term debt	$ 1,998,000,000	$ 385,000,000
Weighted average interest rate on short-term debt outstanding	4.40%	5.10%
Revolving Credit Facility
Short-Term Debt [Line Items]
Long-term debt	$ 0
$2.5 Billion Facility Expiring Dec 2024
Short-Term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	2,500,000,000
$500 Million Facility Expiring Nov 2023
Short-Term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	500,000,000
Commercial paper
Short-Term Debt [Line Items]
Short-term debt	1,383,000,000	$ 200,000,000
Term loans
Short-Term Debt [Line Items]
Short-term debt	598,000,000	159,000,000
Bank borrowings
Short-Term Debt [Line Items]
Short-term debt	$ 17,000,000	$ 26,000,000