Summary of Significant Accounting Policies Equity Ownership (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Equity Securities, FV-NI, Gain (Loss)		$ (39.6)		$ 0.0		$ 242.7	$ 0.0
Investment Owned, Balance, Shares		38,279,580				38,279,580
Proceeds from Equity Method Investment, Distribution		$ 13.3				$ 30.0
Equity in earnings of unconsolidated affiliates		0.0		33.5		$ 0.0	86.7
Equity Securities Sold During Period						73,300,000
Proceeds from Sales of Equity Securities						$ 812.6
Distributions from unconsolidated affiliates				18.4		0.0	36.7
Proceeds from Sale of Interest in Partnership Unit		6.7				175.7
Equity Securities, FV-NI, Unrealized Loss		(39.6)				242.7
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		73.1	$ 279.5	$ 112.9	$ 52.7	352.6	$ 165.6
Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest				25.50%			25.50%
Proportionate Unconsolidated Affiliate Net Income				$ 20.0			$ 59.5
Equity in Earnings Amortization of Basis Difference	[1]			13.5			27.2
Debt and Equity Securities, Unrealized Gain (Loss)		$ (46.3)				$ 67.0
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest				$ 79.0			$ 234.0

[1] Includes loss on dilution, net of proportional basis difference recognition.