Investments (Fair Value of Trading Securities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 1,854	$ 2,065
Corporate bonds [Member] | Fixed Maturity AFS Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	1,416	1,528
ABS [Member] | Fixed Maturity AFS Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	25	32
U.S. government bonds [Member] | Fixed Maturity AFS Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	221	278
Foreign government bonds [Member] | Fixed Maturity AFS Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	25	25
RMBS [Member] | Fixed Maturity AFS Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	104	135
CMBS [Member] | Fixed Maturity AFS Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	4	4
CLOs [Member] | Fixed Maturity AFS Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	10	9
State and municipal bonds [Member] | Fixed Maturity AFS Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	18	22
Hybrid and redeemable preferred securities [Member] | Fixed Maturity AFS Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading securities	$ 31	$ 32