Financial Derivatives (Credit Ratings of Credit Default Swaps) (Details) (Credit Default Swap, Buying Protection [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Credit Derivatives [Line Items]
Notional Amount	$ 110	$ 95
External Credit Rating, Investment Grade [Member]
Credit Derivatives [Line Items]
Notional Amount	95	95
External Credit Rating, Non Investment Grade [Member]
Credit Derivatives [Line Items]
Notional Amount	$ 15