Investments (Realized Gain (Loss) Related To Certain Investments) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Realized gain (loss) related to certain investments
Gain (loss) on other investments		$ (12)	$ (68)	$ (9)
Associated amortization of DAC, VOBA, DSI and DFEL and changes in other contract holder funds		(21)	(24)	(26)
Total realized gain (loss) related to certain investments, pre-tax	[1]	(72)	(250)	(88)
Fixed maturity AFS securities [Member]
Realized gain (loss) related to certain investments
AFS securities. Gross gains	[2]	19	70	43
AFS securities. Gross losses	[2]	(64)	(234)	(99)
Equity AFS securities [Member]
Realized gain (loss) related to certain investments
AFS securities. Gross gains		$ 6	7	$ 3
AFS securities. Gross losses			$ (1)

[1] See "Realized Gain (Loss) Related to Certain Investments" section in Note 5.

[2] These amounts are represented net of related fair value hedging activity. See Note 6 for more information.