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	$ 407
(Increases) attributable to:
Change in DAC, VOBA, DSI and DFEL	1
Less:
Balance as of end-of-period	2,453
Unrealized Gain (Loss) on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	557	$ 3,486
Cumulative effect from adoption of new accounting standard			$ 674
Unrealized holding gains (losses) arising during the period	3,556	(3,063)
Change in foreign currency exchange rate adjustment	14	52
Change in DAC, VOBA, DSI, future contract benefits and other contract holder funds	(928)	958
Income tax benefit (expense)	(563)	432
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	(15)	(18)
Associated amortization of DAC, VOBA, DSI, and DFEL	(1)	(4)
Income tax benefit (expense)	3	5
Less:
Balance as of end-of-period	2,649	2,556
Unrealized OTTI on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	33	44
Cumulative effect from adoption of new accounting standard			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)	4
Decreases attributable to
Changes in fair value, sales, maturities or other settlements of AFS securities	6	(9)
Change in DAC, VOBA, DSI, and DFEL	(2)	(10)
Income tax benefit (expense)	(1)	4
Less:
Balance as of end-of-period	25	38
Unrealized Gain (Loss) on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	139	(29)
Cumulative effect from adoption of new accounting standard			(6)
Unrealized holding gains (losses) arising during the period	(36)	16
Change in foreign currency exchange rate adjustment	(14)	(50)
Decreases attributable to
Change in DAC, VOBA, DSI and DFEL	6	4
Income tax benefit (expense)	10	7
Less:
Reclassification adjustment for gains (losses) included in net income (loss)	8	3
Associated amortization of DAC, VOBA, DSI and DFEL	(1)	(1)
Income tax benefit (expense)	(1)
Balance as of end-of-period	99	(60)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(23)	(14)
Change in foreign currency exchange rate adjustment	3	5
Less:
Balance as of end-of-period	(20)	(9)
Funded Status of Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of beginning-of-year	(299)	(257)
Cumulative effect from adoption of new accounting standard			$ (35)
Less:
Adjustment arising during the period	(1)
Balance as of end-of-period	$ (300)	$ (292)