Income Taxes - Summary of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Current tax expense (benefit)	$ (14.8)	$ 50.2	$ 93.9
Deferred income taxes, net	229.9	278.5	111.0
ITCs	(10.5)	(5.8)	(4.6)
Total income tax expense	$ 204.6	$ 322.9	$ 200.3