The notional amount of derivative settled.

No definition available.

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- Definition

Percentage of total capitalization in the covenant of line of credit facility.

+ References

No definition available.

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- Definition

Amount of short-term borrowing used to support lending to utilities.

+ References

No definition available.

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Maximum aggregate principal amount of short-term borrowing.

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No definition available.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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No definition available.

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- Definition

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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- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

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

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Note 6 - Financing (Details Textual) - USD ($)		1 Months Ended	3 Months Ended
Note 6 - Financing (Details Textual) - USD ($)	Jan. 05, 2023	Mar. 31, 2021	Mar. 31, 2023	Mar. 07, 2023	Feb. 13, 2023	Dec. 31, 2022	Oct. 13, 2022	Jul. 22, 2022
Interest Rate Swap [Member]
Derivative, Notional Amount, Settled			$ 325,000,000.0
Derivative, Gain (Loss) on Derivative, Net			39,500,000
Commercial Paper [Member]
Short-term Borrowing, Maximum Aggregate Principal Amount								$ 1,300,000,000.0
Commercial Paper [Member] \| Parent Company [Member]
Short Term Borrowings Used to Support Lending to Utilities			$ 224.2
Spire [Member] \| Notes Due March 15 2033 [Member]
Debt Instrument, Interest Rate, Stated Percentage				5.80%
Long-Term Debt, Gross				$ 150,000,000.0
Spire Missouri [Member] \| First Mortgage Bond Due 2033 [Member]
Debt Instrument, Interest Rate, Stated Percentage					4.80%
Long-Term Debt, Gross					$ 400,000,000.0
Spire Missouri [Member] \| Unsecured Term Loan [Member]
Debt Instrument, Face Amount	$ 250,000,000.0	$ 250,000,000.0
Debt Instrument, Term (Day)		364 days
Debt Instrument, Interest Rate, Stated Percentage	0.10%
Spire Missouri [Member] \| Unsecured Term Loan [Member] \| London Interbank Offered Rate LIBOR 1 [Member]
Line of Credit Facility, Covenant, Percentage of Total Capitalization						65.00%
Debt Instrument, Basis Spread on Variable Rate	0.80%	0.65%
Spire Gulf [Member] \| Notes Due October 15, 2029 [Member]
Debt Instrument, Interest Rate, Stated Percentage							5.32%
Long-Term Debt, Gross							$ 90,000,000.0
Spire Gulf [Member] \| Notes Due October 15, 2032 [Member]
Debt Instrument, Interest Rate, Stated Percentage							5.41%
Long-Term Debt, Gross							$ 85,000,000.0
Spire Gulf [Member] \| First Mortgage Bonds Due October 15, 2037 [Member]
Debt Instrument, Interest Rate, Stated Percentage							5.61%
Long-Term Debt, Gross							$ 30,000,000.0
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity								1,300,000,000.0
Long-Term Line of Credit, Total						$ 0
Revolving Credit Facility [Member] \| Maximum [Member]
Line of Credit Facility, Covenant, Percentage of Total Capitalization						70.00%
Revolving Credit Facility [Member] \| Spire [Member]
Line of Credit Facility, Maximum Borrowing Capacity								450,000,000.0
Revolving Credit Facility [Member] \| Spire Missouri [Member]
Line of Credit Facility, Maximum Borrowing Capacity								575,000,000.0
Revolving Credit Facility [Member] \| Spire Alabama Inc [Member]
Line of Credit Facility, Maximum Borrowing Capacity								$ 275,000,000.0