Financial Derivatives (Credit Ratings of Credit Default Swaps) (Details) - Credit Default Swap, Buying Protection [Member] - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Credit Derivatives [Line Items]
Notional Amount	$ 98	$ 110
External Credit Rating, Investment Grade [Member]
Credit Derivatives [Line Items]
Notional Amount	83	95
External Credit Rating, Non Investment Grade [Member]
Credit Derivatives [Line Items]
Notional Amount	$ 15	$ 15