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	$ 182,504
Interest Rate Contracts [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	123,248
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	55,784
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	182,504	$ 163,315
Asset Fair Value	7,324	4,384
Liability Fair Value	8,431	4,306
Derivative Investments [Member] \| Interest Rate Contracts [Member] \| Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [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] \| Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [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] \| Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	55,784	43,555
Asset Fair Value	2,819	1,442
Liability Fair Value	1,112	664
Derivative Investments [Member] \| Credit contracts [Member] \| Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	394	55
Derivative Investments [Member] \| Cash Flow Hedges [Member] \| Designated as Hedging Instrument [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	5,309	5,261
Asset Fair Value	940	299
Liability Fair Value	866	296
Derivative Investments [Member] \| Cash Flow Hedges [Member] \| Interest Rate Contracts [Member] \| Designated as Hedging Instrument [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	2,397	2,387
Asset Fair Value	334	108
Liability Fair Value	853	245
Derivative Investments [Member] \| Cash Flow Hedges [Member] \| Foreign currency contracts [Member] \| Designated as Hedging Instrument [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] \| Designated as Hedging Instrument [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	1,170	1,261
Asset Fair Value		123
Liability Fair Value	337	203
Other Assets [Member] \| GLB Direct Embedded Derivatives [Member] \| Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [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] \| Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]
Outstanding derivative instruments with off-balance-sheet risks
Asset Fair Value	728	60
Liability Fair Value		9
Reinsurance Related Embedded Derivatives [Member] \| Reinsurance Related [Member] \| Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]
Outstanding derivative instruments with off-balance-sheet risks
Asset Fair Value	137
Liability Fair Value		327
Future Contract Benefits [Member] \| Indexed Annuity And IUL Contracts [Member] \| Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]
Outstanding derivative instruments with off-balance-sheet risks
Asset Fair Value	799	927
Liability Fair Value	$ 1,380	$ 2,585

Derivative Investments [Member] | Interest Rate Contracts [Member] | Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]

Derivative Investments [Member] | Foreign currency contracts [Member] | Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]

Derivative Investments [Member] | Equity market contracts [Member] | Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]

Derivative Investments [Member] | Credit contracts [Member] | Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]

Derivative Investments [Member] | Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member]

Derivative Investments [Member] | Cash Flow Hedges [Member] | Interest Rate Contracts [Member] | Designated as Hedging Instrument [Member]

Derivative Investments [Member] | Cash Flow Hedges [Member] | Foreign currency contracts [Member] | Designated as Hedging Instrument [Member]

Derivative Investments [Member] | Fair Value Hedges [Member] | Interest Rate Contracts [Member] | Designated as Hedging Instrument [Member]

Other Assets [Member] | GLB Direct Embedded Derivatives [Member] | Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]

Other Liabilities [Member] | GLB Ceded Embedded Derivatives [Member] | Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]

Reinsurance Related Embedded Derivatives [Member] | Reinsurance Related [Member] | Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]

Future Contract Benefits [Member] | Indexed Annuity And IUL Contracts [Member] | Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]