Variable Interest Entities - Activity of Alternative Energy Partnership Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022		Dec. 31, 2021
Variable Interest Entity [Line Items]
Tax (Expense) Benefit Recognized from Alternative Energy Partnership	$ (74.8)	$ (84.4)	[1]	$ (125.6)	[1]
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Fundings	0.0	0.0		80.0
Cash distribution from Investment	2.0	3.3		0.5
Income (Loss) on Investments in Alternative Energy Partnership	2.9	(19.9)		(61.2)
Income Tax Credits Recognized	0.2	4.3		73.9
Tax (Expense) Benefit Recognized from Alternative Energy Partnership	$ (0.7)	$ 3.7		$ 5.1

[1] As of January 1, 2023, the Company adopted ASU 2018-12 using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been recast to reflect application of the new guidance. See Note 2 to the Consolidated Financial Statements for additional information.