Investments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Investments [Abstract]
Reduction of net unrealized gains on investments included in AOCI due to shadow adjustments	$ 712	$ 532
Future capital call commitments for limited partnership investments	384
Mortgage Loan Commitments	59
Commitments to purchase or fund privately placed debt securities	154
Commitments to sell various privately placed debt securities	$ 180