Shares and Stockholders' Equity (Components And Changes In Accumulated OCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	$ 3,327
Less:
Balance as of end-of-year	659	$ 3,327
Unrealized Gain (Loss) on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	3,283	1,687	$ 934
Cumulative effect from adoption of new accounting standard		634
Unrealized holding gains (losses) arising during the year	(5,995)	2,872	1,549
Change in foreign currency exchange rate adjustment	(107)	134	(100)
Change in DAC, VOBA, DSI, future contract benefits and other contract holder funds	1,748	(703)	(460)
Income tax benefit (expense)	923	(745)	(351)
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	(44)	(40)	(155)
Associated amortization of DAC, VOBA, DSI, and DFEL	(19)	(19)	(22)
Income tax benefit (expense)	13	21	62
Less:
Balance as of end-of-year	536	3,283	1,687
Unrealized OTTI on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	39	22	19
Cumulative effect from adoption of new accounting standard		9
(Increases) attributable to:
Gross OTTI recognized in OCI during the period			(53)
Change in DAC, VOBA, DSI and DFEL			12
Income tax benefit (expense)			14
Decreases attributable to
Changes in fair value, sales, maturities or other settlements of AFS securities	(18)	34	51
Change in DAC, VOBA, DSI, and DFEL	(5)	(7)	(7)
Income tax benefit (expense)	4	(10)	(15)
Less:
Balance as of end-of-year	29	39	22
Unrealized Gain (Loss) on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	27	93	157
Cumulative effect from adoption of new accounting standard		6
Unrealized holding gains (losses) arising during the year	40	63	(175)
Change in foreign currency exchange rate adjustment	111	(137)	96
Decreases attributable to
Change in DAC, VOBA, DSI and DFEL	(14)	1	2
Income tax benefit (expense)	(29)	26	27
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	31	31	24
Associated amortization of DAC, VOBA, DSI and DFEL	(3)	(2)	(2)
Income tax benefit (expense)	(6)	(10)	(8)
Balance as of end-of-year	119	27	93
Funded Status of Employee Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(22)	(20)	(19)
Cumulative effect from adoption of new accounting standard		(5)
Less:
Adjustment arising during the year	3	(4)	(2)
Income tax benefit (expense)	(1)	2	1
Balance as of end-of-year	$ (25)	$ (22)	$ (20)