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	$ 3,230
Cumulative effect from adoption of new accounting standards	(6)
Less:
Balance as of end-of-year	407	$ 3,230
Unrealized Gain (Loss) on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	3,486	1,784	$ 991
Cumulative effect from adoption of new accounting standards		674
Unrealized holding gains (losses) arising during the year	(6,274)	3,032	1,600
Change in foreign currency exchange rate adjustment	(107)	134	(99)
Change in DAC, VOBA, DSI, future contract benefits and other contract holder funds	1,748	(705)	(456)
Income tax benefit (expense)	981	(797)	(370)
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	(42)	(39)	(158)
Associated amortization of DAC, VOBA, DSI, and DFEL	(20)	(20)	(23)
Income tax benefit (expense)	13	21	63
Less:
Balance as of end-of-year	557	3,486	1,784
Unrealized OTTI on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	44	25	26
Cumulative effect from adoption of new accounting standards		9
(Increases) attributable to:
Gross OTTI recognized in OCI during the year			(55)
Change in DAC, VOBA, DSI and DFEL			12
Income tax benefit (expense)			15
Decreases attributable to
Changes in fair value, sales, maturities or other settlements of AFS securities	(19)	34	54
Change in DAC, VOBA, DSI, and DFEL	(6)	(5)	(12)
Income tax benefit (expense)	5	(10)	(15)
Less:
Balance as of end-of-year	33	44	25
Unrealized Gain (Loss) on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(29)	49	132
Cumulative effect from adoption of new accounting standards		(6)
Unrealized holding gains (losses) arising during the year	144	27	(215)
Change in foreign currency exchange rate adjustment	111	(137)	96
Decreases attributable to
Change in DAC, VOBA, DSI and DFEL	(13)	2	3
Income tax benefit (expense)	(51)	38	41
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	24	13	14
Associated amortization of DAC, VOBA, DSI and DFEL	(2)	(1)	(1)
Income tax benefit (expense)	(5)	(4)	(5)
Balance as of end-of-year	139	(29)	49
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(14)	(27)	(5)
Change in foreign currency exchange rate adjustment	(9)	13	(22)
Less:
Balance as of end-of-year	(23)	(14)	(27)
Funded Status of Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(257)	(265)	(299)
Cumulative effect from adoption of new accounting standards		(35)
Less:
Adjustment arising during the period	(12)	18	43
Income tax benefit (expense)	5	(10)	(9)
Balance as of end-of-year	$ (299)	$ (257)	$ (265)