Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Assets:
Trading fixed maturities	$ 321		$ 440
Assets of managed investment entities (MIE)	3,225		3,058
Total assets accounted for at fair value	29,316		26,852
Liabilities:
Liabilities of managed investment entities	2,892		2,787
Derivatives in annuity benefits accumulated	465		361
Derivative liability, at fair value	17		23
Total liabilities accounted for at fair value	3,374		3,171
Fixed maturity [Member]
Assets:
Total AFS securities	24,118		21,807
U.S. Government and government agencies [Member]
Assets:
Total AFS securities	388		382
States, municipalities and political subdivisions [Member]
Assets:
Total AFS securities	4,468		3,877
Foreign government [Member]
Assets:
Total AFS securities	260		254
Residential Mortgage Backed Securities [Member]
Assets:
Total AFS securities	4,204		3,848
Commercial Mortgage Backed Securities [Member]
Assets:
Total AFS securities	2,918		2,840
All other corporate [Member]
Assets:
Total AFS securities	11,880		10,606
Equity securities [Member]
Assets:
Total AFS securities	939		928
Variable Annuity Assets (separate accounts) [Member]
Assets:
Variable annuity assets	580	[1]	548	[1]
Other investments [Member]
Assets:
Other Investments	133		71
Level 1 [Member]
Assets:
Trading fixed maturities	0		0
Assets of managed investment entities (MIE)	256		290
Total assets accounted for at fair value	1,269		1,435
Liabilities:
Liabilities of managed investment entities	147		194
Derivatives in annuity benefits accumulated	0		0
Derivative liability, at fair value	0		0
Total liabilities accounted for at fair value	147		194
Level 1 [Member] | Fixed maturity [Member]
Assets:
Total AFS securities	232		257
Level 1 [Member] | U.S. Government and government agencies [Member]
Assets:
Total AFS securities	227		248
Level 1 [Member] | States, municipalities and political subdivisions [Member]
Assets:
Total AFS securities	0		0
Level 1 [Member] | Foreign government [Member]
Assets:
Total AFS securities	0		0
Level 1 [Member] | Residential Mortgage Backed Securities [Member]
Assets:
Total AFS securities	0		0
Level 1 [Member] | Commercial Mortgage Backed Securities [Member]
Assets:
Total AFS securities	0		0
Level 1 [Member] | All other corporate [Member]
Assets:
Total AFS securities	5		9
Level 1 [Member] | Equity securities [Member]
Assets:
Total AFS securities	781		888
Level 1 [Member] | Variable Annuity Assets (separate accounts) [Member]
Assets:
Variable annuity assets	0	[1]	0	[1]
Level 1 [Member] | Other investments [Member]
Assets:
Other Investments	0		0
Level 2 [Member]
Assets:
Trading fixed maturities	321		439
Assets of managed investment entities (MIE)	2,929		2,724
Total assets accounted for at fair value	27,010		24,379
Liabilities:
Liabilities of managed investment entities	0		0
Derivatives in annuity benefits accumulated	0		0
Derivative liability, at fair value	17		23
Total liabilities accounted for at fair value	17		23
Level 2 [Member] | Fixed maturity [Member]
Assets:
Total AFS securities	22,926		20,568
Level 2 [Member] | U.S. Government and government agencies [Member]
Assets:
Total AFS securities	141		134
Level 2 [Member] | States, municipalities and political subdivisions [Member]
Assets:
Total AFS securities	4,410		3,794
Level 2 [Member] | Foreign government [Member]
Assets:
Total AFS securities	260		254
Level 2 [Member] | Residential Mortgage Backed Securities [Member]
Assets:
Total AFS securities	3,833		3,487
Level 2 [Member] | Commercial Mortgage Backed Securities [Member]
Assets:
Total AFS securities	2,896		2,821
Level 2 [Member] | All other corporate [Member]
Assets:
Total AFS securities	11,386		10,078
Level 2 [Member] | Equity securities [Member]
Assets:
Total AFS securities	121		29
Level 2 [Member] | Variable Annuity Assets (separate accounts) [Member]
Assets:
Variable annuity assets	580	[1]	548	[1]
Level 2 [Member] | Other investments [Member]
Assets:
Other Investments	133		71
Level 3 [Member]
Assets:
Trading fixed maturities	0		1
Assets of managed investment entities (MIE)	40		44
Total assets accounted for at fair value	1,037		1,038
Liabilities:
Liabilities of managed investment entities	2,745		2,593
Derivatives in annuity benefits accumulated	465		361
Derivative liability, at fair value	0		0
Total liabilities accounted for at fair value	3,210		2,954
Level 3 [Member] | Fixed maturity [Member]
Assets:
Total AFS securities	960		982
Level 3 [Member] | U.S. Government and government agencies [Member]
Assets:
Total AFS securities	20		0
Level 3 [Member] | States, municipalities and political subdivisions [Member]
Assets:
Total AFS securities	58		83
Level 3 [Member] | Foreign government [Member]
Assets:
Total AFS securities	0		0
Level 3 [Member] | Residential Mortgage Backed Securities [Member]
Assets:
Total AFS securities	371		361
Level 3 [Member] | Commercial Mortgage Backed Securities [Member]
Assets:
Total AFS securities	22		19
Level 3 [Member] | All other corporate [Member]
Assets:
Total AFS securities	489		519
Level 3 [Member] | Equity securities [Member]
Assets:
Total AFS securities	37		11
Level 3 [Member] | Variable Annuity Assets (separate accounts) [Member]
Assets:
Variable annuity assets	0	[1]	0	[1]
Level 3 [Member] | Other investments [Member]
Assets:
Other Investments	$ 0		$ 0

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