Investments (Fair Value And Gross Unrealized Losses In A Continuous Unrealized Loss Position) (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016 USD ($) security	Dec. 31, 2015 USD ($) security
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	$ 2,796	$ 21,873
Greater Than Twelve Months	4,506	3,263
Continuous Unrealized Loss Position, Total	7,302	25,136
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	49	1,411
Greater Than Twelve Months	504	724
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	$ 553	$ 2,135
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	844	2,007
Equity AFS securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	$ 10	$ 47
Greater Than Twelve Months	49
Continuous Unrealized Loss Position, Total	59	47
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	1	6
Greater Than Twelve Months	3
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	4	6
Fixed maturity securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	2,786	21,826
Greater Than Twelve Months	4,457	3,263
Continuous Unrealized Loss Position, Total	7,243	25,089
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	48	1,405
Greater Than Twelve Months	501	724
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	549	2,129
Corporate bonds [Member] | Fixed maturity securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	2,089	20,380
Greater Than Twelve Months	3,419	2,383
Continuous Unrealized Loss Position, Total	5,508	22,763
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	40	1,364
Greater Than Twelve Months	394	623
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	434	1,987
ABS [Member] | Fixed maturity securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	92	213
Greater Than Twelve Months	295	274
Continuous Unrealized Loss Position, Total	387	487
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	1	4
Greater Than Twelve Months	27	29
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	28	33
U.S. government bonds [Member] | Fixed maturity securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months		15
Continuous Unrealized Loss Position, Total		15
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months		2
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses		2
Foreign government bonds [Member] | Fixed maturity securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months		37
Continuous Unrealized Loss Position, Total		37
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months		1
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses		1
RMBS [Member] | Fixed maturity securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	265	627
Greater Than Twelve Months	434	371
Continuous Unrealized Loss Position, Total	699	998
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	4	21
Greater Than Twelve Months	26	22
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	30	43
CMBS [Member] | Fixed maturity securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	19	116
Greater Than Twelve Months	17	11
Continuous Unrealized Loss Position, Total	36	127
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	1	2
Greater Than Twelve Months	1	2
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	2	4
CLOs [Member] | Fixed maturity securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	264	271
Greater Than Twelve Months	74	49
Continuous Unrealized Loss Position, Total	338	320
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	1	2
Greater Than Twelve Months		1
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	1	3
State and municipal bonds [Member] | Fixed maturity securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	45	129
Greater Than Twelve Months	52	27
Continuous Unrealized Loss Position, Total	97	156
Available-for-sale Securities, Continuous Unrealized Loss Position, Gross Unrealized Losses and OTTI
Less Than or Equal to Twelve Months	1	8
Greater Than Twelve Months	4	4
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	5	12
Hybrid and redeemable preferred securities [Member] | Fixed maturity securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Less Than or Equal to Twelve Months	12	38
Greater Than Twelve Months	166	148
Continuous Unrealized Loss Position, Total	178	186
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	49	43
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses	$ 49	$ 44