Basis of Presentation and Principles of Consolidation (Narrative) (Details) $ / shares in Units, $ in Millions	Jun. 11, 2024 $ / shares shares	Sep. 30, 2024 USD ($) $ / shares	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Stock split conversion ratio	2
Class A Common Stock, par value (in dollars per share) | $ / shares	$ 0.001	$ 0.001
Change in the number of authorized common shares | shares	0
Total equity		$ 9,506.1	$ 9,030.6		$ 8,395.8	$ 7,916.5	$ 7,570.9		$ 7,073.5
Common stock		1.2			1.2
Additional paid-in capital		3,457.6			3,100.6
Common Stock
Total equity		1.2	1.2		1.2	1.2	1.2		1.2
Common Stock | Stock Split [Member]
Total equity		0.6	0.6	$ 0.6	0.6	0.6	0.6	$ 0.6	0.6
Additional Paid in Capital
Total equity		3,457.6	3,349.2		3,100.6	3,014.4	2,859.8		2,649.8
Additional Paid in Capital | Stock Split [Member]
Total equity		$ (0.6)	$ (0.6)	$ (0.6)	$ (0.6)	$ (0.6)	$ (0.6)	$ (0.6)	$ (0.6)