Debt - Narrative (Details)				3 Months Ended		6 Months Ended
	Jan. 15, 2025 USD ($)	Mar. 15, 2022 USD ($)	Mar. 10, 2022 USD ($) deferral_period	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)	Mar. 16, 2022 USD ($)	Feb. 15, 2022 USD ($)
Debt Instrument [Line Items]
Long-term debt				$ 942,600,000		$ 942,600,000		$ 1,391,600,000
Interest and other expenses				9,000,000.0	$ 13,900,000	20,400,000	$ 27,900,000
Interest paid, including capitalized interest, operating and investing activities				$ 2,600,000	$ 7,300,000	$ 27,100,000	$ 27,300,000
Senior Notes | Senior Notes, 4.35 Percent Due February 15, 2025
Debt Instrument [Line Items]
Stated interest rate				4.35%		4.35%
Long-term debt, gross	$ 450,000,000.0
Redemption price, percentage	100.00%
Senior Notes | Senior Notes, 2.400 Percent Due September 30, 2030
Debt Instrument [Line Items]
Stated interest rate				2.40%		2.40%
Long-term debt, gross				$ 400,000,000.0		$ 400,000,000.0
Face amount of debt				$ 395,800,000		$ 395,800,000
Effective interest rate				2.52%		2.52%
Long-term debt				$ 397,700,000		$ 397,700,000		397,500,000
Senior Notes | Senior Notes, 3.800 Percent Due February 23, 2033
Debt Instrument [Line Items]
Stated interest rate				3.80%		3.80%
Long-term debt, gross										$ 400,000,000
Effective interest rate				3.95%		3.95%
Long-term debt				$ 396,700,000		$ 396,700,000		396,500,000		$ 395,100,000
Junior Debt | 5.875% Fixed-Rate Reset Junior Subordinated Debentures due 2062
Debt Instrument [Line Items]
Stated interest rate				5.875%		5.875%
Long-term debt, gross			$ 150,000,000
Long-term debt			$ 144,700,000	$ 148,200,000		$ 148,200,000		147,700,000
Debt instrument, basis spread on variable rate			4.14%
Debt instrument, interest deferrals, number of deferral periods | deferral_period			1
Debt instrument, interest deferrals, period			5 years
Revolving Credit Facility | Notes Payable under Revolving Credit Agreement | Second Amended and Restated Credit Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 600,000,000.0							$ 800,000,000.0
Increase in revolving credit borrowing capacity		$ 200,000,000.0
Line of credit facility, amount outstanding				$ 0		$ 0		$ 0