Restricted Securities Available For Sale (Restricted Securities Available For Sale) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Restricted Cash and Cash Equivalents Items [Line Items]
Cost	$ 48.5	$ 53.3
Gross Unrealized Gains	0.0	0.1
Gross Unrealized Losses	0.2	0.2
Total restricted securities available for sale	48.3	53.2
US Government And Agency Securities [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cost	21.8	28.8
Gross Unrealized Gains	0.0	0.1
Gross Unrealized Losses	0.1	0.1
Total restricted securities available for sale	21.7	28.8
Corporate bonds [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cost	17.1	19.1
Gross Unrealized Gains	0.0	0.0
Gross Unrealized Losses	0.1	0.1
Total restricted securities available for sale	17.0	19.0
Asset-backed Securities [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cost	5.5	4.8
Gross Unrealized Gains	0.0	0.0
Gross Unrealized Losses	0.0	0.0
Total restricted securities available for sale	5.5	4.8
Mortgage-backed securities [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cost	4.1	0.6
Gross Unrealized Gains	0.0	0.0
Gross Unrealized Losses	0.0	0.0
Total restricted securities available for sale	$ 4.1	$ 0.6