Shares and Stockholders' Equity (Components And Changes In Accumulated OCI) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	$ 659
(Increases) attributable to:
Change in DAC, VOBA, DSI and DFEL	(1)
Less:
Balance as of end-of-period	2,654
Unrealized Gain (Loss) on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	536	$ 3,283
Cumulative effect from adoption of new accounting standard			$ 634
Unrealized holding gains (losses) arising during the period	3,406	(2,924)
Change in foreign currency exchange rate adjustment	13	53
Change in DAC, VOBA, DSI, future contract benefits and other contract holder funds	(925)	957
Income tax benefit (expense)	(531)	403
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	(14)	(19)
Associated amortization of DAC, VOBA, DSI, and DFEL	1	(4)
Income tax benefit (expense)	3	5
Less:
Balance as of end-of-period	2,509	2,424
Unrealized OTTI on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	29	39
Cumulative effect from adoption of new accounting standard			9
Change in DAC, VOBA, DSI, future contract benefits and other contract holder funds	1
Income tax benefit (expense)	4	(1)
(Increases) attributable to:
Gross OTTI recognized in OCI during the period	(14)
Decreases attributable to
Changes in fair value, sales, maturities or other settlements of AFS securities	5	(9)
Change in DAC, VOBA, DSI, and DFEL	(2)	(10)
Income tax benefit (expense)	(1)	4
Less:
Balance as of end-of-period	22	32
Unrealized Gain (Loss) on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	119	27
Cumulative effect from adoption of new accounting standard			6
Unrealized holding gains (losses) arising during the period	53	(83)
Change in foreign currency exchange rate adjustment	(14)	(50)
Decreases attributable to
Change in DAC, VOBA, DSI and DFEL	4	4
Income tax benefit (expense)	(9)	28
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	9	6
Associated amortization of DAC, VOBA, DSI and DFEL	(3)	(1)
Income tax benefit (expense)	(1)	(1)
Balance as of end-of-period	148	(72)
Funded Status of Employee Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(25)	(22)
Cumulative effect from adoption of new accounting standard			$ (5)
Less:
Balance as of end-of-period	$ (25)	$ (27)