Investments (Fair Value And Gross Unrealized Losses In A Continuous Unrealized Loss Position) (Details) $ in Millions	Jun. 30, 2018 USD ($) security	Dec. 31, 2017 USD ($) security
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	$ 32,167	$ 5,844
Greater Than Twelve Months	5,590	6,063
Fair Value - Total	37,757	11,907
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	1,130	89
Greater Than Twelve Months	620	374
Losses - Total	$ 1,750	$ 463
Total number of AFS securities in an unrealized loss position | security	3,092	1,128
Equity Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months		$ 22
Greater Than Twelve Months		8
Fair Value - Total		30
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months		14
Greater Than Twelve Months		3
Losses - Total		17
Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months		5,822
Greater Than Twelve Months		6,055
Fair Value - Total		11,877
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months		75
Greater Than Twelve Months		371
Losses - Total		446
Corporate Bonds [Member] | Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	$ 29,697	4,854
Greater Than Twelve Months	4,512	4,893
Fair Value - Total	34,209	9,747
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	1,070	68
Greater Than Twelve Months	513	288
Losses - Total	1,583	356
ABS [Member] | Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	171	62
Greater Than Twelve Months	135	151
Fair Value - Total	306	213
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	2	1
Greater Than Twelve Months	13	15
Losses - Total	15	16
U.S. Government Bonds [Member] | Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	113	156
Greater Than Twelve Months	18	19
Fair Value - Total	131	175
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	1
Greater Than Twelve Months	2	1
Losses - Total	3	1
RMBS [Member] | Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	760	302
Greater Than Twelve Months	607	641
Fair Value - Total	1,367	943
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	27	4
Greater Than Twelve Months	58	36
Losses - Total	85	40
CMBS [Member] | Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	525	113
Greater Than Twelve Months	58	60
Fair Value - Total	583	173
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	16
Greater Than Twelve Months	4	3
Losses - Total	20	3
CLOs [Member] | Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	639	281
Greater Than Twelve Months	57	72
Fair Value - Total	696	353
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	7	2
Losses - Total	7	2
State And Municipal Bonds [Member] | Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	215	34
Greater Than Twelve Months	85	93
Fair Value - Total	300	127
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	5
Greater Than Twelve Months	9	6
Losses - Total	14	6
Hybrid And Redeemable Preferred Securities [Member] | Fixed Maturity AFS Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	47	20
Greater Than Twelve Months	118	126
Fair Value - Total	165	146
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	2
Greater Than Twelve Months	21	22
Losses - Total	$ 23	$ 22