Long-term Debt (Tables)

12 Months Ended

Sep. 30, 2019

Debt Disclosure [Abstract]

Schedule of Composition of Long-term Debt

The composition of long-term debt as of September 30 is shown in the following tables.

	2019			2018
Spire
2.55% Senior Notes, due August 15, 2019	$	—		$	125.0
2.52% Senior Notes, due September 1, 2021		35.0			35.0
3.31% Notes Payable, due December 15, 2022		25.0			25.0
3.54% Senior Notes, due February 27, 2024		150.0			150.0
3.13% Senior Notes, due September 1, 2026		130.0			130.0
3.93% Senior Notes, due March 15, 2027		100.0			100.0
4.70% Senior Notes, due August 15, 2044		250.0			250.0
Total principal of Spire Missouri long-term debt (see below)		930.0			880.0
Total principal of Spire Alabama long-term debt (see below)		415.0			325.0
Other subsidiaries' long-term debt:
4.14% First Mortgage Bonds, due September 30, 2021		20.0			20.0
5.00% First Mortgage Bonds, due September 30, 2031		42.0			42.0
3.52% First Mortgage Bonds, due September 30, 2049		40.0			—
Non-interest-bearing Note, due December 27, 2022		—			10.0
Total principal of long-term debt		2,137.0			2,092.0
Less: Unamortized discounts and debt issuance costs		(14.4	)		(16.4	)
Less: Current portion		(40.0	)		(175.5	)
Long-term debt, excluding current portion	$	2,082.6		$	1,900.1
Spire Missouri
Floating-rate note due December 1, 2021	$	100.0		$	—
First Mortgage Bonds:
5.5% Series, due May 1, 2019		—			50.0
3.0% Series, due March 15, 2023		55.0			55.0
3.4% Series, due August 15, 2023		250.0			250.0
3.4% Series, due March 15, 2028		45.0			45.0
7.0% Series, due June 1, 2029		25.0			25.0
7.9% Series, due September 15, 2030		30.0			30.0
3.68% Series, due September 15, 2032		50.0			50.0
6.0% Series, due May 1, 2034		100.0			100.0
6.15% Series, due June 1, 2036		55.0			55.0
4.625% Series, due August 15, 2043		100.0			100.0
4.23% Series, due September 15, 2047		70.0			70.0
4.38% Series, due September 15, 2057		50.0			50.0
Total principal of Spire Missouri long-term debt		930.0			880.0
Less: Unamortized discounts and debt issuance costs		(5.0	)		(5.6	)
Less: Current portion		—			(50.0	)
Spire Missouri long-term debt, excluding current portion	$	925.0		$	824.4
Spire Alabama
5.20% Notes, due January 15, 2020	$	40.0		$	40.0
3.86% Notes, due December 22, 2021		50.0			50.0
3.21% Notes, due September 15, 2025		35.0			35.0
5.90% Notes, due January 15, 2037		45.0			45.0
4.31% Notes, due December 1, 2045		80.0			80.0
3.92% Notes, due January 15, 2048		45.0			45.0
4.64% Notes, due January 15, 2049		90.0			—
4.02% Notes, due January 15, 2058		30.0			30.0
Total principal of Spire Alabama long-term debt		415.0			325.0
Less: Unamortized discounts and debt issuance costs		(2.8	)		(2.4	)
Less: Current portion		(40.0	)		—
Spire Alabama long-term debt, excluding current portion	$	372.2		$	322.6

Schedule of Maturities of Long-term Debt

Maturities of long-term debt for Spire on a consolidated basis, Spire Missouri and Spire Alabama for the five fiscal years after September 30, 2019 are as follows:

	2020		2021		2022		2023		2024
Spire	$	40.0	$	55.0	$	150.0	$	330.0	$	150.0
Spire Missouri		—		—		100.0		305.0		—
Spire Alabama		40.0		—		50.0		—		—