Acquisition and Investments Schedule Of Amounts Due To And From Affiliates (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Amounts due from affiliates	$ 5.5	$ 15.1
Amounts due to affiliates	0.4	2.1
BRI [Member]
Related Party Transaction [Line Items]
Amounts due from affiliates	4.4	9.0
Amounts due to affiliates	0.0	0.0
BDL [Member]
Related Party Transaction [Line Items]
Amounts due from affiliates	1.1	6.1
Amounts due to affiliates	0.0	0.0
Other Affiliates [Member]
Related Party Transaction [Line Items]
Amounts due from affiliates	0.0	0.0
Amounts due to affiliates	$ 0.4	$ 2.1