Income Taxes (Schedule of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized tax benefit — beginning of year	$ 391.1	$ 92.1	$ 96.3		$ 185.7
Additions for current year tax positions	13.4		0.0	$ 0.0
Additions for prior year tax positions	35.7		154.9	20.0
Reductions for prior year tax positions	(5.2)		(11.7)	(5.8)
Settlements	(8.9)		(112.5)	(32.9)
Reductions due to expirations of statute of limitations	0.0		(34.9)	$ (70.7)
Addition due to acquisition	264.0	0.0	0.0
Unrecognized tax benefit — end of year	$ 391.1	$ 92.1	$ 96.3