Activity in the Allowance for Credit Losses (Details) - Commercial Real Estate Portfolio Segment - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Financing Receivable, Allowance for Credit Losses
Allowance Balance at Beginning of Year	$ 2.0	$ 4.5	$ 1.5	$ 1.5
Provision for Loan Losses	0.0	0.0	0.5	3.0
Charge-offs, Net of Recoveries	(2.0)	0.0	(2.0)	0.0
Allowance Balance at End of Period	$ 0.0	$ 4.5	$ 0.0	$ 4.5