Shares And Stockholders' Equity (Components And Changes In Accumulated OCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	$ 407
Cumulative effect from adoption of new accounting standards		$ (6)
(Increases) attributable to:
Change in DAC, VOBA, DSI and DFEL	1
Less:
Balance as of end-of-period	5,673	407
Unrealized Gain (Loss) on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	557	3,486	$ 1,784
Cumulative effect from adoption of new accounting standards		674
Unrealized holding gains (losses) arising during the period	9,267	(6,274)	3,032
Change in foreign currency exchange rate adjustment	46	(107)	134
Change in DAC, VOBA, DSI, future contract benefits and other contract holder funds	(2,462)	1,748	(705)
Income tax benefit (expense)	(1,457)	981	(797)
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	(28)	(42)	(39)
Associated amortization of DAC, VOBA, DSI, and DFEL	(12)	(20)	(20)
Income tax benefit (expense)	8	13	21
Less:
Balance as of end-of-period	5,983	557	3,486
Unrealized OTTI on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	33	44	25
Cumulative effect from adoption of new accounting standards		9
(Increases) attributable to:
Gross OTTI recognized in OCI during the period	(16)
Change in DAC, VOBA, DSI and DFEL	1
Income tax benefit (expense)	3
Decreases attributable to
Changes in fair value, sales, maturities or other settlements of AFS securities	31	(19)	34
Change in DAC, VOBA, DSI, and DFEL	(1)	(6)	(5)
Income tax benefit (expense)	(6)	5	(10)
Less:
Balance as of end-of-period	45	33	44
Unrealized Gain (Loss) on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	139	(29)	49
Cumulative effect from adoption of new accounting standards		(6)
Unrealized holding gains (losses) arising during the period	(93)	144	27
Change in foreign currency exchange rate adjustment	(52)	111	(137)
Decreases attributable to
Change in DAC, VOBA, DSI and DFEL	(4)	(13)	2
Income tax benefit (expense)	31	(51)	38
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	42	24	13
Associated amortization of DAC, VOBA, DSI and DFEL	(1)	(2)	(1)
Income tax benefit (expense)	(9)	(5)	(4)
Balance as of end-of-period	(11)	139	(29)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(23)	(14)	(27)
Change in foreign currency exchange rate adjustment	6	(9)	13
Less:
Balance as of end-of-period	(17)	(23)	(14)
Funded Status of Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(299)	(257)	(265)
Cumulative effect from adoption of new accounting standards		(35)
Less:
Adjustment arising during the period	(20)	(12)	18
Income tax benefit (expense)	(8)	5	(10)
Balance as of end-of-period	$ (327)	$ (299)	$ (257)