Investment Securities (Fair Value Measurements) (Details) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Investment [Line Items]
Maximum price difference provided by pricing services	$ 1.3
Fair value, investment-related liabilities	81.0	86.3
Minimum
Investment [Line Items]
Maximum percentage of price difference provided by pricing services	5.00%
Maximum price difference provided by pricing services	$ 1.0