Derivative Instruments (Outstanding Derivative Instruments With Off-Balance-Sheet Risks) (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts		$ 110,350	$ 104,926
Asset Fair Value		2,563	2,005
Liability Fair Value		2,563	3,194
Interest rate contracts [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	[1]	77,382
Foreign currency contracts [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts	[2]	1,826
Equity market contracts [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts		31,090
Credit contracts [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts		52
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	[3],[4]	903
Liability Fair Value	[3],[4]		371
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	[3],[4]	51
Liability Fair Value	[3],[4]	67
Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member]
Outstanding derivative instruments with off-balance-sheet risks
Notional Amounts		4,811	4,729
Asset Fair Value		125	221
Liability Fair Value		163	132
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	[5]	72,937	70,290
Asset Fair Value	[5]	657	985
Liability Fair Value	[5]	127	701
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	[5]	22	14
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	[5]	31,090	28,315
Asset Fair Value	[5]	562	541
Liability Fair Value	[5]	557	616
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	[5]	3,007	3,552
Asset Fair Value	[5]	46	68
Liability Fair Value	[5]	84	122
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	[5]	1,804	1,177
Asset Fair Value	[5]	79	153
Liability Fair Value	[5]	79	10
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	[5]	1,438	1,512
Asset Fair Value	[5]	254	258
Liability Fair Value	[5]	174	182
Other liabilities [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	[5]	52	66
Reinsurance related embedded derivatives [Member] | Embedded derivatives - Reinsurance related [Member] | Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member]
Outstanding derivative instruments with off-balance-sheet risks
Liability Fair Value	[6]	57	53
Future contract benefits [Member] | Indexed annuity and 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	[3],[7]	11
Liability Fair Value	[3],[7]	$ 1,418	$ 1,139

[1] As of December 31, 2017, the latest maturity date for which we were hedging our exposure to the variability in future cash flows for these instruments was April 2067.

[2] As of December 31, 2017, the latest maturity date for which we were hedging our exposure to the variability in future cash flows for these instruments was September 2049.

[3] Reported in other assets on our Consolidated Balance Sheets.

[4] Reported in other liabilities on our Consolidated Balance Sheets.

[5] Reported in derivative investments and other liabilities on our Consolidated Balance Sheets.

[6] Reported in reinsurance related embedded derivatives on our Consolidated Balance Sheets.

[7] Reported in future contract benefits on our Consolidated Balance Sheets.