Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Assets:
Trading fixed maturities	$ 309		$ 440
Assets of managed investment entities (MIE)	3,102		3,058
Total assets accounted for at fair value	28,918		26,852
Liabilities:
Liabilities of managed investment entities	2,753		2,787
Derivatives in annuity benefits accumulated	497		361
Derivative liability, at fair value	18		23
Total liabilities accounted for at fair value	3,268		3,171
Level 1 [Member]
Assets:
Trading fixed maturities	0		0
Assets of managed investment entities (MIE)	221		290
Total assets accounted for at fair value	1,306		1,435
Liabilities:
Liabilities of managed investment entities	247		194
Derivatives in annuity benefits accumulated	0		0
Derivative liability, at fair value	0		0
Total liabilities accounted for at fair value	247		194
Level 2 [Member]
Assets:
Trading fixed maturities	308		439
Assets of managed investment entities (MIE)	2,846		2,724
Total assets accounted for at fair value	26,579		24,379
Liabilities:
Liabilities of managed investment entities	0		0
Derivatives in annuity benefits accumulated	0		0
Derivative liability, at fair value	18		23
Total liabilities accounted for at fair value	18		23
Level 3 [Member]
Assets:
Trading fixed maturities	1		1
Assets of managed investment entities (MIE)	35		44
Total assets accounted for at fair value	1,033		1,038
Liabilities:
Liabilities of managed investment entities	2,506		2,593
Derivatives in annuity benefits accumulated	497		361
Derivative liability, at fair value	0		0
Total liabilities accounted for at fair value	3,003		2,954
Fixed Maturity [Member]
Assets:
Total AFS securities	23,746		21,807
Fixed Maturity [Member] | Level 1 [Member]
Assets:
Total AFS securities	202		257
Fixed Maturity [Member] | Level 2 [Member]
Assets:
Total AFS securities	22,583		20,568
Fixed Maturity [Member] | Level 3 [Member]
Assets:
Total AFS securities	961		982
U.S. Government and government agencies [Member]
Assets:
Total AFS securities	361		382
U.S. Government and government agencies [Member] | Level 1 [Member]
Assets:
Total AFS securities	198		248
U.S. Government and government agencies [Member] | Level 2 [Member]
Assets:
Total AFS securities	143		134
U.S. Government and government agencies [Member] | Level 3 [Member]
Assets:
Total AFS securities	20		0
States, municipalities and political subdivisions [Member]
Assets:
Total AFS securities	4,326		3,877
States, municipalities and political subdivisions [Member] | Level 1 [Member]
Assets:
Total AFS securities	0		0
States, municipalities and political subdivisions [Member] | Level 2 [Member]
Assets:
Total AFS securities	4,268		3,794
States, municipalities and political subdivisions [Member] | Level 3 [Member]
Assets:
Total AFS securities	58		83
Foreign government [Member]
Assets:
Total AFS securities	264		254
Foreign government [Member] | Level 1 [Member]
Assets:
Total AFS securities	0		0
Foreign government [Member] | Level 2 [Member]
Assets:
Total AFS securities	264		254
Foreign government [Member] | Level 3 [Member]
Assets:
Total AFS securities	0		0
Residential Mortgage Backed Securities [Member]
Assets:
Total AFS securities	4,320		3,848
Residential Mortgage Backed Securities [Member] | Level 1 [Member]
Assets:
Total AFS securities	0		0
Residential Mortgage Backed Securities [Member] | Level 2 [Member]
Assets:
Total AFS securities	3,953		3,487
Residential Mortgage Backed Securities [Member] | Level 3 [Member]
Assets:
Total AFS securities	367		361
Commercial Mortgage Backed Securities [Member]
Assets:
Total AFS securities	2,945		2,840
Commercial Mortgage Backed Securities [Member] | Level 1 [Member]
Assets:
Total AFS securities	0		0
Commercial Mortgage Backed Securities [Member] | Level 2 [Member]
Assets:
Total AFS securities	2,924		2,821
Commercial Mortgage Backed Securities [Member] | Level 3 [Member]
Assets:
Total AFS securities	21		19
All other corporate [Member]
Assets:
Total AFS securities	11,530		10,606
All other corporate [Member] | Level 1 [Member]
Assets:
Total AFS securities	4		9
All other corporate [Member] | Level 2 [Member]
Assets:
Total AFS securities	11,031		10,078
All other corporate [Member] | Level 3 [Member]
Assets:
Total AFS securities	495		519
Equity securities [Member]
Assets:
Total AFS securities	1,031		928
Equity securities [Member] | Level 1 [Member]
Assets:
Total AFS securities	883		888
Equity securities [Member] | Level 2 [Member]
Assets:
Total AFS securities	112		29
Equity securities [Member] | Level 3 [Member]
Assets:
Total AFS securities	36		11
Variable Annuity Assets (separate accounts) [Member]
Assets:
Variable annuity assets	577	[1]	548	[1]
Variable Annuity Assets (separate accounts) [Member] | Level 1 [Member]
Assets:
Variable annuity assets	0	[1]	0	[1]
Variable Annuity Assets (separate accounts) [Member] | Level 2 [Member]
Assets:
Variable annuity assets	577	[1]	548	[1]
Variable Annuity Assets (separate accounts) [Member] | Level 3 [Member]
Assets:
Variable annuity assets	0	[1]	0	[1]
Other Investments [Member]
Assets:
Other Investments	153		71
Other Investments [Member] | Level 1 [Member]
Assets:
Other Investments	0		0
Other Investments [Member] | Level 2 [Member]
Assets:
Other Investments	153		71
Other Investments [Member] | Level 3 [Member]
Assets:
Other Investments	$ 0		$ 0

[1] Variable annuity liabilities equal the fair value of variable annuity assets.