Shares and Stockholders' Equity (Components And Changes In Accumulated OCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	$ 1,566
(Increases) attributable to:
Gross OTTI recognized in OCI during the period		$ (55)	$ (30)
Less:
Balance as of end-of-period	3,230	1,566
Unrealized Gain (Loss) on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	1,784	991	3,213
Unrealized holding gains (losses) arising during the year	3,032	1,600	(4,541)
Change in foreign currency exchange rate adjustment	134	(99)	(45)
Change in DAC, VOBA, DSI, future contract benefits and other contract holder funds	(705)	(456)	1,294
Income tax benefit (expense)	(797)	(370)	1,147
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	(39)	(158)	145
Associated amortization of DAC, VOBA, DSI, and DFEL	(20)	(23)	(27)
Income tax benefit (expense)	21	63	(41)
Less:
Balance as of end-of-period	3,486	1,784	991
Unrealized OTTI on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	25	26	26
(Increases) attributable to:
Gross OTTI recognized in OCI during the period		(55)	(30)
Change in DAC, VOBA, DSI and DFEL		12	4
Income tax benefit (expense)		15	9
Decreases attributable to
Changes in fair value, sales, maturities or other settlements of AFS securities	34	54	43
Change in DAC, VOBA, DSI, and DFEL	(5)	(12)	(17)
Income tax benefit (expense)	(10)	(15)	(9)
Less:
Balance as of end-of-period	44	25	26
Unrealized Gain (Loss) on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	49	132	139
Unrealized holding gains (losses) arising during the year	27	(215)	(241)
Change in foreign currency exchange rate adjustment	(137)	96	48
Decreases attributable to
Change in DAC, VOBA, DSI and DFEL	2	3	2
Income tax benefit (expense)	38	41	66
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	13	14	(183)
Associated amortization of DAC, VOBA, DSI and DFEL	(1)	(1)	1
Income tax benefit (expense)	(4)	(5)	64
Balance as of end-of-period	(29)	49	132
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(27)	(5)	(3)
Change in foreign currency exchange rate adjustment	13	(22)	(2)
Less:
Balance as of end-of-period	(14)	(27)	(5)
Funded Status of Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(265)	(299)	(279)
Less:
Adjustment arising during the period	18	43	(21)
Income tax benefit (expense)	(10)	(9)	1
Balance as of end-of-period	$ (257)	$ (265)	$ (299)