Shares and Stockholder's Equity (Components And Changes In Accumulated OCI) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	$ 5,836
Less:
Balance as of end-of-period	3,773
Unrealized Gain (Loss) on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	5,637	$ 536
Cumulative effect from adoption of new accounting standards			$ 40
Unrealized holding gains (losses) arising during the period	(4,357)	3,406
Change in foreign currency exchange rate adjustment	(150)	13
Change in DAC, VOBA, DSI, future contract benefits and other contract holder funds	1,263	(925)
Income tax benefit (expense)	691	(531)
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	(3)	(14)
Associated amortization of DAC, VOBA, DSI, and DFEL	27	1
Income tax benefit (expense)	(5)	3
Less:
Balance as of end-of-period	3,105	2,509
Unrealized OTTI on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	40	29
Cumulative effect from adoption of new accounting standards			$ (40)
Income tax benefit (expense)		4
(Increases) attributable to:
Gross OTTI recognized in OCI during the period		(14)
Change in DAC, VOBA, DSI and DFEL		1
Decreases attributable to
Changes in fair value, sales, maturities or other settlements of AFS securities		5
Change in DAC, VOBA, DSI, and DFEL		(2)
Income tax benefit (expense)		(1)
Less:
Balance as of end-of-period		22
Unrealized Gain (Loss) on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	181	119
Unrealized holding gains (losses) arising during the period	553	53
Change in foreign currency exchange rate adjustment	153	(14)
Decreases attributable to
Change in DAC, VOBA, DSI and DFEL	(48)	4
Income tax benefit (expense)	(140)	(9)
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	12	9
Associated amortization of DAC, VOBA, DSI and DFEL	(1)	(3)
Income tax benefit (expense)	(2)	(1)
Balance as of end-of-period	690	148
Funded Status of Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(22)	(25)
Less:
Adjustment arising during the period
Balance as of end-of-period	$ (22)	$ (25)