Summary of Significant Accounting Policies Equity Ownership (Details) - USD ($) shares in Thousands, $ in Millions		3 Months Ended						9 Months Ended
		Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Equity Securities, FV-NI, Gain (Loss)		$ 39.4			$ 0.0			$ 282.1	$ 0.0
Proceeds from Equity Method Investment, Distribution		4.0						34.0
Equity in earnings of unconsolidated affiliates		0.0			41.2			$ 0.0	127.9
Equity Securities Sold During Period								95,400
Proceeds from Sales of Equity Securities								$ 1,067.2
Distributions from unconsolidated affiliates					18.3			0.0	55.0
Equity Securities, FV-NI, Unrealized Loss		39.4						282.1
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		$ 262.8	$ 73.1	$ 279.5	$ 252.5	$ 112.9	$ 52.7	$ 615.4	$ 418.1
Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest					25.50%				25.50%
Proportionate Unconsolidated Affiliate Net Income					$ 27.5				$ 87.0
Equity in Earnings Amortization of Basis Difference	[1]				13.7				40.9
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest					$ 107.0				$ 341.0

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