Selected Quarterly Financial Information (unaudited) (Textuals) (Details) - USD ($) $ in Millions	3 Months Ended					12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Net Loss(gain) from natural disaster, net of Insurance recoveries	$ 93.4	$ 7.1	$ 31.9	$ 46.4	$ 38.6	$ 178.8	$ 38.3