Derivative Instruments (Outstanding Derivative Instruments With Off-Balance-Sheet Risks) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	$ 180,389
Interest rate contracts [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	121,404
Foreign currency contracts [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	3,078
Equity market contracts [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	55,513
Credit contracts [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	394
Total Derivative Instruments [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	180,389	$ 161,115
Asset Fair Value	11,302	4,261
Liability Fair Value	7,570	4,621
Derivative investments [Member] | Interest rate contracts [Member] | Non-Qualifying Hedging [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	119,681	112,921
Asset Fair Value	1,890	1,082
Liability Fair Value	140	219
Derivative investments [Member] | Foreign currency contracts [Member] | Non-Qualifying Hedging [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	166	262
Asset Fair Value	11	1
Liability Fair Value		3
Derivative investments [Member] | Equity market contracts [Member] | Non-Qualifying Hedging [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	55,513	43,283
Asset Fair Value	2,819	1,442
Liability Fair Value	1,112	664
Derivative investments [Member] | Credit contracts [Member] | Non-Qualifying Hedging [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	394	55
Derivative investments [Member] | Cash Flow Hedges [Member] | Qualifying Hedges [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	4,096	4,048
Asset Fair Value	940	299
Liability Fair Value	13	63
Derivative investments [Member] | Cash Flow Hedges [Member] | Interest rate contracts [Member] | Qualifying Hedges [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	1,184	1,174
Asset Fair Value	334	108
Liability Fair Value		12
Derivative investments [Member] | Cash Flow Hedges [Member] | Foreign currency contracts [Member] | Qualifying Hedges [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	2,912	2,874
Asset Fair Value	606	191
Liability Fair Value	13	51
Derivative investments [Member] | Fair Value Hedges [Member] | Interest rate contracts [Member] | Qualifying Hedges [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	539	546
Liability Fair Value	329	202
Other Assets [Member] | GLB Direct Embedded Derivatives [Member] | Non-Qualifying Hedging [Member]
Outstanding derivative instruments with off-balance-sheet risks
Asset Fair Value		450
Liability Fair Value	4,596
Other Liabilities [Member] | GLB Ceded Embedded Derivatives [Member] | Non-Qualifying Hedging [Member]
Outstanding derivative instruments with off-balance-sheet risks
Asset Fair Value	4,589	60
Liability Fair Value		510
Reinsurance Related Embedded Derivatives [Member] | Embedded derivatives - Reinsurance related [Member] | Non-Qualifying Hedging [Member]
Outstanding derivative instruments with off-balance-sheet risks
Asset Fair Value	254
Liability Fair Value		375
Future Contract Benefits [Member] | Indexed Annuity And IUL Contracts [Member] | Non-Qualifying Hedging [Member]
Outstanding derivative instruments with off-balance-sheet risks
Asset Fair Value	799	927
Liability Fair Value	$ 1,380	$ 2,585