Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Amount of cumulative increase (decrease) in fair value of hedged liability in fair value hedge, attributable to hedged risk.

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Amount of long-term debt and lease obligation, classified as noncurrent.

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Amount of long-term debt and lease obligation, classified as current.

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Weighted average interest rate of long-term debt outstanding calculated at point in time.

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Debt (Long-term Debt) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Nov. 18, 2021	Sep. 30, 2021
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 7,309.3		$ 7,684.7
Less: Unamortized discount and debt issuance costs	(45.4)		(50.4)
Less: Fair value hedge accounting adjustments	(77.1)		0.5
Total Long-term Debt	7,634.1		7,634.8
Less: Current portion of long-term debt	(548.3)		(484.5)
Less: Long-term debt – related party	(652.0)		(274.6)
Long-term Debt	6,433.8		6,875.7
Variable Interest Entity, Primary Beneficiary [Member] \| NEOM Green Hydrogen Company
Debt Instrument [Line Items]
Less: Long-term debt – related party	(447.3)		0.0
Medium-term Notes \| Series E 7.6% due 2026
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 17.2		17.2
Interest rate, weighted average	7.60%
Senior Notes \| Note 3.0% due 2022
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 0.0		400.0
Interest rate, stated percentage	3.00%	3.00%
Senior Notes \| Note 2.75% due 2023
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 400.0		400.0
Interest rate, stated percentage	2.75%
Senior Notes \| Note 3.35% due 2024
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 400.0		400.0
Interest rate, stated percentage	3.35%
Senior Notes \| Note 1.50% due 2026
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 550.0		550.0
Interest rate, stated percentage	1.50%
Senior Notes \| Note 1.85% due 2027
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 650.0		650.0
Interest rate, stated percentage	1.85%
Senior Notes \| Note 2.05% due 2030
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 900.0		900.0
Interest rate, stated percentage	2.05%
Senior Notes \| Note 2.70% due 2040
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 750.0		750.0
Interest rate, stated percentage	2.70%
Senior Notes \| Note 2.80% due 2050
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 950.0		950.0
Interest rate, stated percentage	2.80%
Bonds \| Variable-rate industrial revenue bonds 1.59% due 2035 to 2050
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 618.9		618.9
Interest rate, weighted average	1.59%
Bonds \| Other variable-rate 3.42% due 2024 to 2032
Debt Instrument [Line Items]
Interest rate, weighted average	3.42%
Bonds \| Eurobonds 1.0% due 2025
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 294.1		347.4
Interest rate, stated percentage	1.00%
Bonds \| Eurobonds 0.50% due 2028
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 490.1		579.1
Interest rate, stated percentage	0.50%
Bonds \| Eurobonds 0.80% due 2032
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 490.1		579.1
Interest rate, stated percentage	0.80%
Bonds \| Saudi Riyal Loan Facility 4.10% due 2023
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 195.6		0.0
Interest rate, stated percentage	4.10%
Bonds \| New Taiwan Dollar 1.86% due 2023 to 2028
Debt Instrument [Line Items]
Interest rate, stated percentage	1.86%
Bonds \| New Taiwan Dollar 2.66% due 2026 to 2030
Debt Instrument [Line Items]
Interest rate, stated percentage	2.66%
Bonds \| Other Foreign due 2023
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 0.1		0.3
Foreign credit facilities \| Other variable-rate 3.42% due 2024 to 2032
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	41.4		14.4
Foreign credit facilities \| New Taiwan Dollar 1.86% due 2023 to 2028
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	189.0		161.8
Foreign credit facilities \| New Taiwan Dollar 2.66% due 2026 to 2030
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	31.5		0.0
Related Party \| Chinese Renminbi 5.5% due 2023 to 2027
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 321.5		355.0
Interest rate, stated percentage	5.50%
Related Party \| Chinese Renminbi 5.7% due 2033
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 12.2		3.4
Interest rate, stated percentage	5.70%
Finance Lease Obligations \| Foreign 11.3% due 2023 to 2036
Debt Instrument [Line Items]
Long-term Debt, Principal Amount	$ 7.6		$ 8.1
Interest rate, weighted average	11.30%