Derivative Instruments (Non Hedging Derivatives and Embedded Derivatives Effect on Income Statement) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	$ (33)	$ 91	$ (170)
Other revenues	(360)	(392)	(363)
Gain Loss On Investments Related To Change In Fair Value Of Derivatives Excluding Embedded Derivatives	59	4	0
Indexed annuity products	(704)	(697)	(425)
Not Designated as Hedging Instrument [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	(25)	(37)	(1)
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	76	65	(21)
Not Designated as Hedging Instrument [Member] | Future [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	(47)	(46)	21
Not Designated as Hedging Instrument [Member] | Currency Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	(7)	0	(4)
Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	5	1	0
Not Designated as Hedging Instrument [Member] | Consumer Price Index Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	16	(18)	(10)
Not Designated as Hedging Instrument [Member] | Credit Default Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	16	30	(2)
Not Designated as Hedging Instrument [Member] | Equity [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	0	(40)	7
Not Designated as Hedging Instrument [Member] | Longevity Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Other revenues	0	(13)	(9)
Not Designated as Hedging Instrument [Member] | Mortality Swap [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Other revenues	0	(1)	0
Not Designated as Hedging Instrument [Member] | Embedded Derivatives In Modified Coinsurance Or Funds Withheld Arrangements [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	(62)	11	(13)
Not Designated as Hedging Instrument [Member] | Embedded Derivatives In Indexed Annuity [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Indexed annuity products	(30)	(57)	(27)
Not Designated as Hedging Instrument [Member] | Embedded Derivatives In Variable Annuity [Member]
Income Affect Of Non Hedging Derivatives [Line Items]
Total investment related gains (losses), net	$ 8	$ 5	$ (15)