Investments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 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	1,311	$ 1,111
Fixed maturity securities and equity securities in the energy and metals and mining sectors, at fair value	2,446
Fixed maturity securities and equity securities in the energy and metals and mining sectors, amortized cost or cost basis	2,464
Fixed maturity securities and equity securities in the energy and metals and mining sectors, at fair value, unrealized loss position	1,069
Fixed maturity securities and equity securities in the energy and metals and mining sectors, amortized cost or cost basis, unrealized loss position	1,202
Derivative, Notional Amount	178	179
Derivative Asset, Fair Value, Gross Asset	1
Derivative Liability, Fair Value, Gross Liability		$ (5)
Future Capital Call Commitments	371
Mortgage Loan Commitments	10
Commitments To Purchase Or Fund Additional Amounts	163
Commitments To Sell Various Privately Placed Debt Securities	$ 166