Investments and Derivative Instruments (Details 5) (USD $) In Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
Available-for-sale Securities, Continuous Unrealized Loss Position
Less Than 12 Months, Amortized Cost	$ 14,556	$ 18,786
Less Than 12 Months, Fair Value	14,100	18,039
Less Than 12 Months, Unrealized Losses	(451)	(742)
12 Months or More, Amortized Cost	13,208	15,599
12 Months or More, Fair Value	11,161	12,811
12 Months or More, Unrealized Losses	(2,009)	(2,754)
Amortized Cost	27,764	34,385
Fair Value	25,261	30,850
Unrealized Losses	(2,460)	(3,496)
ABS [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position
Less Than 12 Months, Amortized Cost	264	302
Less Than 12 Months, Fair Value	257	290
Less Than 12 Months, Unrealized Losses	(7)	(12)
12 Months or More, Amortized Cost	1,331	1,410
12 Months or More, Fair Value	1,030	1,026
12 Months or More, Unrealized Losses	(301)	(384)
Amortized Cost	1,595	1,712
Fair Value	1,287	1,316
Unrealized Losses	(308)	(396)
CDOs [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position
Less Than 12 Months, Amortized Cost	337	321
Less Than 12 Months, Fair Value	317	293
Less Than 12 Months, Unrealized Losses	(20)	(28)
12 Months or More, Amortized Cost	2,570	2,724
12 Months or More, Fair Value	2,237	2,274
12 Months or More, Unrealized Losses	(333)	(450)
Amortized Cost	2,907	3,045
Fair Value	2,554	2,567
Unrealized Losses	(353)	(478)
CMBS [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position
Less Than 12 Months, Amortized Cost	1,334	556
Less Than 12 Months, Fair Value	1,282	530
Less Than 12 Months, Unrealized Losses	(52)	(26)
12 Months or More, Amortized Cost	2,495	3,962
12 Months or More, Fair Value	2,214	3,373
12 Months or More, Unrealized Losses	(281)	(589)
Amortized Cost	3,829	4,518
Fair Value	3,496	3,903
Unrealized Losses	(333)	(615)
Corporate [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position
Less Than 12 Months, Amortized Cost	5,789	5,533
Less Than 12 Months, Fair Value	5,590	5,329
Less Than 12 Months, Unrealized Losses	(194)	(199)
12 Months or More, Amortized Cost	3,617	4,017
12 Months or More, Fair Value	3,162	3,435
12 Months or More, Unrealized Losses	(417)	(548)
Amortized Cost	9,406	9,550
Fair Value	8,752	8,764
Unrealized Losses	(611)	(747)
Foreign govt./govt. agencies [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position
Less Than 12 Months, Amortized Cost	182	356
Less Than 12 Months, Fair Value	180	349
Less Than 12 Months, Unrealized Losses	(2)	(7)
12 Months or More, Amortized Cost	53	78
12 Months or More, Fair Value	47	68
12 Months or More, Unrealized Losses	(6)	(10)
Amortized Cost	235	434
Fair Value	227	417
Unrealized Losses	(8)	(17)
Municipal [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position
Less Than 12 Months, Amortized Cost	4,340	7,485
Less Than 12 Months, Fair Value	4,249	7,173
Less Than 12 Months, Unrealized Losses	(91)	(312)
12 Months or More, Amortized Cost	1,016	1,046
12 Months or More, Fair Value	872	863
12 Months or More, Unrealized Losses	(144)	(183)
Amortized Cost	5,356	8,531
Fair Value	5,121	8,036
Unrealized Losses	(235)	(495)
RMBS [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position
Less Than 12 Months, Amortized Cost	810	1,744
Less Than 12 Months, Fair Value	791	1,702
Less Than 12 Months, Unrealized Losses	(19)	(42)
12 Months or More, Amortized Cost	1,424	1,567
12 Months or More, Fair Value	1,026	1,147
12 Months or More, Unrealized Losses	(398)	(420)
Amortized Cost	2,234	3,311
Fair Value	1,817	2,849
Unrealized Losses	(417)	(462)
U.S. Treasuries [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position
Less Than 12 Months, Amortized Cost	1,289	2,436
Less Than 12 Months, Fair Value	1,228	2,321
Less Than 12 Months, Unrealized Losses	(61)	(115)
12 Months or More, Amortized Cost	133	158
12 Months or More, Fair Value	100	119
12 Months or More, Unrealized Losses	(33)	(39)
Amortized Cost	1,422	2,594
Fair Value	1,328	2,440
Unrealized Losses	(94)	(154)
Fixed maturities, AFS [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position
Less Than 12 Months, Amortized Cost	14,345	18,733
Less Than 12 Months, Fair Value	13,894	17,987
Less Than 12 Months, Unrealized Losses	(446)	(741)
12 Months or More, Amortized Cost	12,639	14,962
12 Months or More, Fair Value	10,688	12,305
12 Months or More, Unrealized Losses	(1,913)	(2,623)
Amortized Cost	26,984	33,695
Fair Value	24,582	30,292
Unrealized Losses	(2,359)	(3,364)
Equity securities, AFS [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position
Less Than 12 Months, Amortized Cost	211	53
Less Than 12 Months, Fair Value	206	52
Less Than 12 Months, Unrealized Losses	(5)	(1)
12 Months or More, Amortized Cost	569	637
12 Months or More, Fair Value	473	506
12 Months or More, Unrealized Losses	(96)	(131)
Amortized Cost	780	690
Fair Value	679	558
Unrealized Losses	$ (101)	$ (132)