Fair Value of Financial Instruments (Fair Value of Assets and Liabilities on a Recurring Basis) (Details) - USD ($) $ in Millions		Jun. 30, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		$ 257,319	$ 233,897
Liabilities measured at fair value		(3,257)	(1,793)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		1,413	1,340
Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		249,245	227,067
Liabilities measured at fair value		(854)	(317)
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		6,661	5,490
Liabilities measured at fair value		(2,403)	(1,476)
Corporate Bonds [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		84,790	80,348
Corporate Bonds [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		81,142	77,079
Corporate Bonds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		3,648	3,269
ABS [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		1,117	966
ABS [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		904	937
ABS [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		213	29
U.S. Government Bonds [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		430	417
U.S. Government Bonds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		413	399
U.S. Government Bonds [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		17	18
Foreign Government Bonds [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		440	448
Foreign Government Bonds [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		327	339
Foreign Government Bonds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		113	109
RMBS [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		3,292	3,373
RMBS [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		3,292	3,366
RMBS [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value			7
CMBS [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		965	804
CMBS [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		963	802
CMBS [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		2	2
CLOs [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		2,425	1,730
CLOs [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		2,318	1,625
CLOs [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		107	105
State And Municipal Bonds [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		5,669	5,345
State And Municipal Bonds [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		5,669	5,345
Hybrid And Redeemable Preferred Securities [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		605	593
Hybrid And Redeemable Preferred Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		73	67
Hybrid And Redeemable Preferred Securities [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		454	451
Hybrid And Redeemable Preferred Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity AFS Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		78	75
Trading Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		4,522	1,950
Trading Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		49	43
Trading Securities [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		3,950	1,840
Trading Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		523	67
Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		196	99
Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		40	16
Equity Securities [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		88	58
Equity Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		68	25
Derivative Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value	[1]	2,125	1,432
Derivative Investments [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value	[1]	1,230	727
Derivative Investments [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value	[1]	895	705
Other Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		153	150
Other Investments [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		153	150
Cash And Invested Cash [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		3,314	2,345
Cash And Invested Cash [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		3,314	2,345
GLB Direct Embedded Derivatives [Member] | Other Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value			123
GLB Direct Embedded Derivatives [Member] | Other Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value		(1)
GLB Direct Embedded Derivatives [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value			123
GLB Direct Embedded Derivatives [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value		(1)
GLB Ceded Embedded Derivatives [Member] | Other Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		111	72
GLB Ceded Embedded Derivatives [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		111	72
Indexed Annuity And IUL Contracts [Member] | Other Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		903	902
Indexed Annuity And IUL Contracts [Member] | Future Contract Benefits [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value		(1,973)	(1,305)
Indexed Annuity And IUL Contracts [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		903	902
Indexed Annuity And IUL Contracts [Member] | Significant Unobservable Inputs (Level 3) [Member] | Future Contract Benefits [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value		(1,973)	(1,305)
Separate Account Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		146,262	132,800
Separate Account Assets [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		685	665
Separate Account Assets [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		145,577	132,135
Reinsurance Related Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value		(310)	(3)
Reinsurance Related Embedded Derivatives [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value		(310)	(3)
Derivative Liabilities [Member] | Other Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value	[1]	(973)	(485)
Derivative Liabilities [Member] | Significant Observable Inputs (Level 2) [Member] | Other Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value	[1]	(544)	(314)
Derivative Liabilities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value	[1]	$ (429)	$ (171)

[1] Derivative investment assets and liabilities are presented within the fair value hierarchy on a gross basis by derivative type and not on a master netting basis by counterparty.