Investments (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Investments [Abstract]
Reduction of net unrealized gains on investments included in AOCI due to shadow adjustments	$ 1,022	$ 1,288
Future capital call commitments for limited partnership investments	295
Mortgage loan commitments	6
Commitments to purchase or fund privately placed debt securities	134
Commitments to sell various privately placed debt securities	$ 79