Investments (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Investments [Abstract]
Gains (Losses) on Extinguishment of Debt	$ 8
Reduction of net unrealized gains on investments included in AOCI due to shadow adjustments	1,681	$ 1,111
Derivative, Notional Amount	175	179
Derivative Asset, Fair Value, Gross Asset	8
Derivative Liability, Fair Value, Gross Liability		$ (5)
Future Capital Call Commitments	393
Mortgage Loan Commitments	40
Commitments To Purchase Or Fund Additional Amounts	205
Commitments To Sell Various Privately Placed Debt Securities	$ 163