Fair Value Measurements (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Liabilities of Managed Investment Entities [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial liabilities, Beginning Balance	$ (2,258)	$ 0
Consolidate Managed Investment Entities		(2,084)
Total realized/unrealized Gains (losses) included in Net income	0	(220)
Purchases, sales, issuances and settlements		46
Purchases and issuances	(401)
Sales and settlements	66
Financial liabilities, Ending Balance	(2,593)	(2,258)
Embedded derivatives [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial liabilities, Beginning Balance	(190)	(113)	(96)
Total realized/unrealized Gains (losses) included in Net income	(29)	(20)	(29)
Purchases, sales, issuances and settlements		(57)	12
Purchases and issuances	(200)
Sales and settlements	24
Financial liabilities, Ending Balance	(395)	(190)	(113)
States, municipalities and political subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	20	23
Total realized/unrealized gains (losses) included in Other comprehensive income loss	4	1
Purchases, sales, issuances and settlements		(4)
Purchases and issuances	58
Sales and settlements	(4)
Transfer into Level 3	17	17
Transfer out of Level 3	(12)	(17)
Financial assets, Ending Balance	83	20
Residential Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	312	435
Total realized/unrealized gains (losses) included in Net income	3	7
Total realized/unrealized gains (losses) included in Other comprehensive income loss	(9)	26
Purchases, sales, issuances and settlements		17
Purchases and issuances	42
Sales and settlements	(38)
Transfer into Level 3	127	27
Transfer out of Level 3	(76)	(200)
Financial assets, Ending Balance	361	312
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	6	0
Total realized/unrealized gains (losses) included in Net income	1
Purchases, sales, issuances and settlements		6
Purchases and issuances	9
Transfer into Level 3	13
Transfer out of Level 3	(10)
Financial assets, Ending Balance	19	6
Assets of Managed Investment Entities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	48	0
Consolidate Managed Investment Entities		90
Total realized/unrealized gains (losses) included in Net income	(8)	8
Purchases, sales, issuances and settlements		(16)
Purchases and issuances	32
Sales and settlements	(18)
Transfer into Level 3	9	26
Transfer out of Level 3	(19)	(60)
Financial assets, Ending Balance	44	48
All other corporate [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	436	311
Consolidate Managed Investment Entities		(6)
Total realized/unrealized gains (losses) included in Net income	2	(10)
Total realized/unrealized gains (losses) included in Other comprehensive income loss	15	10
Purchases, sales, issuances and settlements		100
Purchases and issuances	236
Sales and settlements	(72)
Transfer into Level 3	90	118
Transfer out of Level 3	(188)	(87)
Financial assets, Ending Balance	519	436
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	21	25	44
Total realized/unrealized gains (losses) included in Net income			(13)
Total realized/unrealized gains (losses) included in Other comprehensive income loss	1	(1)	1
Purchases and issuances	2		1
Sales and settlements	(2)
Transfer into Level 3	2
Transfer out of Level 3	(13)	(3)	(8)
Financial assets, Ending Balance	11	21	25
Other Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance			5
Transfer out of Level 3			(5)
Trading fixed maturities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	3	1	1
Total realized/unrealized gains (losses) included in Net income			0
Purchases, sales, issuances and settlements		4
Transfer into Level 3		2
Transfer out of Level 3	(2)	(4)
Financial assets, Ending Balance	1	3	1
AFS Fixed Maturities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance			706
Total realized/unrealized gains (losses) included in Net income			7
Total realized/unrealized gains (losses) included in Other comprehensive income loss			89
Purchases, sales, issuances and settlements			292
Transfer out of Level 3			(325)
Financial assets, Ending Balance			$ 769