Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions		Total		Florida City Gas	Common Stock [Member]		Common Stock [Member] Florida City Gas	[1]	Additional Paid-In Capital [Member]	Additional Paid-In Capital [Member] Florida City Gas	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Deferred Compensation [Member]	Treasury Stock, Common
Shares, Issued	[1],[2]				17,741,000
Stockholders' Equity Attributable to Parent		$ 832.7	[2]		$ 8.6	[1]			$ 380.0		$ 445.5	$ (1.4)	$ 7.1	$ (7.1)
Net Income		87.2									87.2
Stock Issued During Period, Value, Acquisitions				$ 366.5			$ 2.2			$ 364.3
Other comprehensive loss		(1.4)										(1.4)
Dividends		(44.0)									(44.0)
Share-based compensation, shares	[1],[2],[3],[4]				55,000
Share-based compensation	[3],[4]	5.1			$ 0.0	[1]			5.1					0.0
Treasury stock activities	[2]	$ 0.0											2.0	(2.0)
Business Combination, Consideration Transferred, Equity Interest, Share Issued, Number of Shares	[1],[2]			4,439,000
Common Stock, Dividends, Per Share, Declared		$ 2.3050
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation		20,000
Shares, Issued	[1],[2]				22,235,000
Stockholders' Equity Attributable to Parent		$ 1,246.1	[2]		$ 10.8	[1]			749.4		488.7	(2.8)	9.1	(9.1)
Net Income		118.6									118.6
Other comprehensive loss		1.1										1.1
Dividends		(57.0)									(57.0)
Stock Issued, Value, During The Period Shares Retirement Savings Plan And Dividend Reinvestment Plan	[5]	74.5							74.2
Stock Issued During The Period Value Retirement Savings Plan And Dividend Reinvestment Plan	[1],[5]				$ (0.3)
Share-based compensation, shares	[1],[2],[3],[4]				37,000
Share-based compensation	[3],[4]	6.9			$ 0.0	[1]			6.9
Treasury stock activities	[2]	$ 0.0											0.7	(0.7)
Stock Issued During Period, Shares, Dividend Reinvestment Plan	[1],[2],[5]				627,000
Common Stock, Dividends, Per Share, Declared		$ 2.510
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation		14,000
Shares, Issued	[1],[2]				22,899,000
Stockholders' Equity Attributable to Parent		$ 1,390.2			$ 11.1	[1]			830.5		550.3	(1.7)	9.8	(9.8)
Preferred Stock, Shares Authorized		2,000,000
Net Income		$ 140.3									140.3
Other comprehensive loss		(1.0)										(1.0)
Dividends		(63.8)									(63.8)
Stock Issued, Value, During The Period Shares Retirement Savings Plan And Dividend Reinvestment Plan	[5]	123.5							123.0
Stock Issued During The Period Shares Retirement Savings Plan And Dividend Reinvestment Plan	[1],[2],[5]				961,000
Stock Issued During The Period Value Retirement Savings Plan And Dividend Reinvestment Plan	[1],[5]				$ (0.5)
Share-based compensation, shares	[1],[2],[3],[4]				36,000
Share-based compensation	[3],[4]	9.3			$ 0.0	[1]			9.3
Treasury stock activities	[2]	$ 0.0											2.8	(2.8)
Common Stock, Dividends, Per Share, Declared		$ 2.695
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation		8,000
Shares, Issued	[1],[2]				23,896,000
Stockholders' Equity Attributable to Parent		$ 1,598.5			$ 11.6	[1]			$ 962.8		$ 626.8	$ (2.7)	$ 12.6	$ (12.6)
Preferred Stock, Shares Authorized		2,000,000.0

[1] 2.0 million shares of preferred stock at $0.01 par value per share have been authorized. No preferred shares have been issued or are outstanding; accordingly, no information has been included in the Consolidated Statements of Stockholders’ Equity.

[2] Includes 129 thousand, 114 thousand and 108 thousand shares at December 31, 2025, 2024 and 2023, respectively, held in a Rabbi Trust related to our Non-Qualified Deferred Compensation Plan

[3] Includes amounts for shares issued for directors’ compensation.

[4] The shares issued under the SICP are net of shares withheld for employee taxes. For 2025, 2024 and 2023, we withheld 8 thousand, 14 thousand and 20 thousand shares, respectively, for taxes.

[5] Includes shares issued under the Retirement Savings Plan, DRIP and/or ATM, as applicable.