Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Assets:
Total AFS securities	$ 22,981	$ 21,807
Trading fixed maturities	447	440
Assets of managed investment entities (MIE)	2,825	3,058
Total assets accounted for at fair value	28,079	26,852
Liabilities:
Liabilities of managed investment entities	2,502	2,787
Derivatives in annuity benefits accumulated	512	395
Derivative liability, at fair value	26	23
Total liabilities accounted for at fair value	3,040	3,205
Level 1 [Member]
Assets:
Total AFS securities	239	257
Assets of managed investment entities (MIE)	153	290
Total assets accounted for at fair value	1,383	1,435
Liabilities:
Liabilities of managed investment entities	73	194
Total liabilities accounted for at fair value	73	194
Level 2 [Member]
Assets:
Total AFS securities	21,759	20,568
Trading fixed maturities	446	439
Assets of managed investment entities (MIE)	2,618	2,724
Total assets accounted for at fair value	25,617	24,379
Liabilities:
Derivative liability, at fair value	26	23
Total liabilities accounted for at fair value	26	23
Level 3 [Member]
Assets:
Total AFS securities	983	982
Trading fixed maturities	1	1
Assets of managed investment entities (MIE)	54	44
Total assets accounted for at fair value	1,079	1,038
Liabilities:
Liabilities of managed investment entities	2,429	2,593
Derivatives in annuity benefits accumulated	512	395
Total liabilities accounted for at fair value	2,941	2,988
Variable Annuity Assets (separate accounts) [Member]
Assets:
Variable annuity assets	574	548
Variable Annuity Assets (separate accounts) [Member] | Level 2 [Member]
Assets:
Variable annuity assets	574	548
Other Investments [Member]
Assets:
Other Investments	131	71
Other Investments [Member] | Level 2 [Member]
Assets:
Other Investments	131	71
U.S. Government and government agencies [Member]
Assets:
Total AFS securities	379	382
U.S. Government and government agencies [Member] | Level 1 [Member]
Assets:
Total AFS securities	234	248
U.S. Government and government agencies [Member] | Level 2 [Member]
Assets:
Total AFS securities	145	134
States, municipalities and political subdivisions [Member]
Assets:
Total AFS securities	4,067	3,877
States, municipalities and political subdivisions [Member] | Level 2 [Member]
Assets:
Total AFS securities	3,981	3,794
States, municipalities and political subdivisions [Member] | Level 3 [Member]
Assets:
Total AFS securities	86	83
Foreign government [Member]
Assets:
Total AFS securities	256	254
Foreign government [Member] | Level 2 [Member]
Assets:
Total AFS securities	256	254
Residential Mortgage Backed Securities [Member]
Assets:
Total AFS securities	4,189	3,848
Residential Mortgage Backed Securities [Member] | Level 2 [Member]
Assets:
Total AFS securities	3,869	3,487
Residential Mortgage Backed Securities [Member] | Level 3 [Member]
Assets:
Total AFS securities	320	361
Commercial Mortgage Backed Securities [Member]
Assets:
Total AFS securities	2,886	2,840
Commercial Mortgage Backed Securities [Member] | Level 2 [Member]
Assets:
Total AFS securities	2,866	2,821
Commercial Mortgage Backed Securities [Member] | Level 3 [Member]
Assets:
Total AFS securities	20	19
All other corporate [Member]
Assets:
Total AFS securities	11,204	10,606
All other corporate [Member] | Level 1 [Member]
Assets:
Total AFS securities	5	9
All other corporate [Member] | Level 2 [Member]
Assets:
Total AFS securities	10,642	10,078
All other corporate [Member] | Level 3 [Member]
Assets:
Total AFS securities	557	519
Equity securities [Member]
Assets:
Total AFS securities	1,121	928
Equity securities [Member] | Level 1 [Member]
Assets:
Total AFS securities	991	888
Equity securities [Member] | Level 2 [Member]
Assets:
Total AFS securities	89	29
Equity securities [Member] | Level 3 [Member]
Assets:
Total AFS securities	$ 41	$ 11