Fair Value of Financial Instruments (Fair Value Of Assets And Liabilities On A Recurring Basis) (Details) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Fair value of plan assets		$ 118	$ 115
Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		268,178	232,028
Liabilities measured at fair value		(4,621)	(1,986)
Fair value of plan assets		118	115
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		1,187	1,158
Significant Observable Inputs (Level 2) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		255,692	222,998
Liabilities measured at fair value		(659)	(314)
Fair value of plan assets		118	115
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		11,299	7,872
Liabilities measured at fair value		(3,962)	(1,672)
Corporate Bonds [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		87,779	79,549
Corporate Bonds [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		80,801	73,897
Corporate Bonds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		6,978	5,652
U.S. Government Bonds [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		403	386
U.S. Government Bonds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		391	368
U.S. Government Bonds [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		7	18
U.S. Government Bonds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		5
Foreign Government Bonds [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		388	444
Foreign Government Bonds [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		298	335
Foreign Government Bonds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		90	109
RMBS [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		3,008	3,164
RMBS [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		2,997	3,157
RMBS [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		11	7
CMBS [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		1,083	803
CMBS [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		1,082	801
CMBS [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		1	2
CLOs [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		4,883	2,678
CLOs [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		4,615	2,544
CLOs [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		268	134
State And Municipal Bonds [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		5,685	5,184
State And Municipal Bonds [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		5,685	5,184
Hybrid And Redeemable Preferred Securities [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		544	579
Hybrid And Redeemable Preferred Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		77	66
Hybrid And Redeemable Preferred Securities [Member] | Significant Observable Inputs (Level 2) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		389	438
Hybrid And Redeemable Preferred Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Maturity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		78	75
Trading Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		4,602	1,869
Trading Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		50	43
Trading Securities [Member] | Significant Observable Inputs (Level 2) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		3,886	1,759
Trading Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		666	67
Equity Securities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		103	99
Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		25	16
Equity Securities [Member] | Significant Observable Inputs (Level 2) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		48	58
Equity Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		30	25
Derivative Investments [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value	[1]	2,824	1,340
Derivative Investments [Member] | Significant Observable Inputs (Level 2) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value	[1]	1,089	636
Derivative Investments [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value	[1]	1,735	704
Cash And Invested Cash [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		1,879	1,848
Cash And Invested Cash [Member] | Significant Observable Inputs (Level 2) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		1,879	1,848
GLB Direct Embedded Derivatives [Member] | Other Assets [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		450	123
GLB Direct Embedded Derivatives [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Assets [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		450	123
GLB Ceded Embedded Derivatives [Member] | Other Assets [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		60	72
GLB Ceded Embedded Derivatives [Member] | Other Liabilities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value		(510)	(196)
GLB Ceded Embedded Derivatives [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Assets [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		60	72
GLB Ceded Embedded Derivatives [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Liabilities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value		(510)	(196)
Indexed Annuity And IUL Contracts [Member] | Other Assets [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		927	902
Indexed Annuity And IUL Contracts [Member] | Future Contract Benefits [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value		(2,585)	(1,305)
Indexed Annuity And IUL Contracts [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Assets [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		927	902
Indexed Annuity And IUL Contracts [Member] | Significant Unobservable Inputs (Level 3) [Member] | Future Contract Benefits [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value		(2,585)	(1,305)
Separate Account Assets [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		153,560	132,800
Separate Account Assets [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		644	665
Separate Account Assets [Member] | Significant Observable Inputs (Level 2) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value		152,916	132,135
Reinsurance Related Embedded Derivatives [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value			188
Liabilities measured at fair value		(375)
Reinsurance Related Embedded Derivatives [Member] | Significant Observable Inputs (Level 2) [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets measured at fair value			188
Liabilities measured at fair value		(375)
Derivative Liabilities [Member] | Other Liabilities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value	[1]	(1,151)	(485)
Derivative Liabilities [Member] | Significant Observable Inputs (Level 2) [Member] | Other Liabilities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value	[1]	(284)	(314)
Derivative Liabilities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Liabilities [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities measured at fair value	[1]	$ (867)	$ (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