Shares and Stockholder's Equity (Components And Changes In Accumulated OCI) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 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	4,525
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 standards			$ 634
Unrealized holding gains (losses) arising during the period	6,623	(4,667)
Change in foreign currency exchange rate adjustment	2	(49)
Change in DAC, VOBA, DSI, future contract benefits and other contract holder funds	(1,904)	1,402
Income tax benefit (expense)	(1,004)	702
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	(22)	(29)
Associated amortization of DAC, VOBA, DSI, and DFEL	(6)	(2)
Income tax benefit (expense)	6	7
Less:
Balance as of end-of-period	4,275	1,329
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 standards			9
Change in DAC, VOBA, DSI, future contract benefits and other contract holder funds	1
Income tax benefit (expense)	4
(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	17	(6)
Change in DAC, VOBA, DSI, and DFEL	(4)	(11)
Income tax benefit (expense)	(3)	3
Less:
Balance as of end-of-period	30	34
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 standards			6
Unrealized holding gains (losses) arising during the period	189	(45)
Change in foreign currency exchange rate adjustment	(5)	50
Decreases attributable to
Change in DAC, VOBA, DSI and DFEL	(4)	(4)
Income tax benefit (expense)	(38)
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	21	13
Associated amortization of DAC, VOBA, DSI and DFEL	(1)	(9)
Income tax benefit (expense)	(4)	(1)
Balance as of end-of-period	245	31
Funded Status of Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(25)	(22)
Cumulative effect from adoption of new accounting standards			$ (5)
Less:
Balance as of end-of-period	$ (25)	$ (27)