Investing Activities Debt Securities Narrative (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013 security	Dec. 31, 2012 security
Investments, Debt and Equity Securities [Abstract]
Unrealized losses on below-investment-grade debt securities depressed of amortized cost (percent)	20.00%	20.00%
Unrealized losses on below-investment-grade debt securities depressed of amortized cost	$ 1.0	$ 21.6
Unrealized losses on below-investment-grade debt securities depressed of amortized cost for more than 12 month, amount	$ 0.8	$ 21.6
Unrealized losses on below-investment-grade debt securities depressed of amortized cost for more than 12 month (percent)	20.00%	20.00%
Available-for-sale securities in an unrealized loss position for over twelve months (number of securities)	79	89