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

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	sr_
Data Type:	xbrli:monetaryItemType
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- Definition

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

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-Topic 835
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Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

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-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
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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.

+ References

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
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- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
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-Section 45
-Paragraph 14
-Subparagraph (b)
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Balance Type:	debit
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- Definition

Amount of cash outflow for short-term and long-term debt. Excludes payment of lease obligation.

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-SubTopic 10
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-Subparagraph (b)
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+ Details

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Balance Type:	credit
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- Details

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Note 6 - Financing (Details Textual) - USD ($) $ in Thousands			1 Months Ended
	Apr. 05, 2024	Jan. 03, 2024	Feb. 29, 2024	Mar. 31, 2024	Feb. 28, 2021
Remarketable Notes [Member]
Debt Instrument, Face Amount					$ 175,000
Debt Instrument, Interest Rate, Stated Percentage					0.75%
Senior Note [Member]
Debt Instrument, Face Amount			$ 175,000
Debt Instrument, Interest Rate, Stated Percentage			5.30%
Proceeds from Issuance of Debt			$ 173,500
Commercial Paper [Member] \| Parent Company [Member]
Short Term Borrowings Used to Support Lending to Utilities				$ 319,800
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%
Spire Missouri [Member] \| Loans Payable [Member]
Debt Instrument, Face Amount		$ 200,000
Spire Missouri [Member] \| Loans Payable [Member] \| Subsequent Event [Member]
Repayments of Debt	$ 50,000
Spire Missouri [Member] \| Loans Payable [Member] \| Secured Overnight Financing Rate (SOFR) [Member]
Debt Instrument, Basis Spread on Variable Rate		0.10%
Spire Missouri [Member] \| Loans Payable [Member] \| Adjusted SOFR [Member[
Debt Instrument, Basis Spread on Variable Rate		0.90%
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity				$ 1,300,000
Long-Term Line of Credit				$ 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
Revolving Credit Facility [Member] \| Spire Missouri [Member]
Line of Credit Facility, Maximum Borrowing Capacity				575,000
Revolving Credit Facility [Member] \| Spire Alabama Inc [Member]
Line of Credit Facility, Maximum Borrowing Capacity				$ 275,000