Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Assets:
Trading fixed maturities	$ 293		$ 321
Assets of managed investment entities (MIE)	2,973		3,225
Total assets accounted for at fair value	30,295		29,316
Liabilities:
Liabilities of managed investment entities	2,603		2,892
Derivatives in annuity benefits accumulated	577		465
Derivative liability, at fair value	12		17
Total liabilities accounted for at fair value	3,192		3,374
Level 1 [Member]
Assets:
Trading fixed maturities
Assets of managed investment entities (MIE)	335		256
Total assets accounted for at fair value	1,466		1,269
Liabilities:
Liabilities of managed investment entities	121		147
Derivatives in annuity benefits accumulated
Derivative liability, at fair value
Total liabilities accounted for at fair value	121		147
Level 2 [Member]
Assets:
Trading fixed maturities	293		321
Assets of managed investment entities (MIE)	2,607		2,929
Total assets accounted for at fair value	27,805		27,010
Liabilities:
Liabilities of managed investment entities
Derivatives in annuity benefits accumulated
Derivative liability, at fair value	12		17
Total liabilities accounted for at fair value	12		17
Level 3 [Member]
Assets:
Trading fixed maturities
Assets of managed investment entities (MIE)	31		40
Total assets accounted for at fair value	1,024		1,037
Liabilities:
Liabilities of managed investment entities	2,482		2,745
Derivatives in annuity benefits accumulated	577		465
Derivative liability, at fair value
Total liabilities accounted for at fair value	3,059		3,210
Fixed Maturity [Member]
Assets:
Total AFS securities	25,035		24,118
Fixed Maturity [Member] | Level 1 [Member]
Assets:
Total AFS securities	178		232
Fixed Maturity [Member] | Level 2 [Member]
Assets:
Total AFS securities	23,942		22,926
Fixed Maturity [Member] | Level 3 [Member]
Assets:
Total AFS securities	915		960
U.S. Government and government agencies [Member]
Assets:
Total AFS securities	312		388
U.S. Government and government agencies [Member] | Level 1 [Member]
Assets:
Total AFS securities	163		227
U.S. Government and government agencies [Member] | Level 2 [Member]
Assets:
Total AFS securities	129		141
U.S. Government and government agencies [Member] | Level 3 [Member]
Assets:
Total AFS securities	20		20
States, municipalities and political subdivisions [Member]
Assets:
Total AFS securities	4,816		4,468
States, municipalities and political subdivisions [Member] | Level 1 [Member]
Assets:
Total AFS securities
States, municipalities and political subdivisions [Member] | Level 2 [Member]
Assets:
Total AFS securities	4,753		4,410
States, municipalities and political subdivisions [Member] | Level 3 [Member]
Assets:
Total AFS securities	63		58
Foreign government [Member]
Assets:
Total AFS securities	242		260
Foreign government [Member] | Level 1 [Member]
Assets:
Total AFS securities
Foreign government [Member] | Level 2 [Member]
Assets:
Total AFS securities	242		260
Foreign government [Member] | Level 3 [Member]
Assets:
Total AFS securities
Residential Mortgage Backed Securities [Member]
Assets:
Total AFS securities	4,153		4,204
Residential Mortgage Backed Securities [Member] | Level 1 [Member]
Assets:
Total AFS securities
Residential Mortgage Backed Securities [Member] | Level 2 [Member]
Assets:
Total AFS securities	3,824		3,833
Residential Mortgage Backed Securities [Member] | Level 3 [Member]
Assets:
Total AFS securities	329		371
Commercial Mortgage Backed Securities [Member]
Assets:
Total AFS securities	2,846		2,918
Commercial Mortgage Backed Securities [Member] | Level 1 [Member]
Assets:
Total AFS securities
Commercial Mortgage Backed Securities [Member] | Level 2 [Member]
Assets:
Total AFS securities	2,818		2,896
Commercial Mortgage Backed Securities [Member] | Level 3 [Member]
Assets:
Total AFS securities	28		22
Asset-backed Securities [Member]
Assets:
Total AFS securities	2,234		1,640
Asset-backed Securities [Member] | Level 1 [Member]
Assets:
Total AFS securities
Asset-backed Securities [Member] | Level 2 [Member]
Assets:
Total AFS securities	2,054		1,387
Asset-backed Securities [Member] | Level 3 [Member]
Assets:
Total AFS securities	180		253
All other corporate [Member]
Assets:
Total AFS securities	10,432		10,240
All other corporate [Member] | Level 1 [Member]
Assets:
Total AFS securities	15		5
All other corporate [Member] | Level 2 [Member]
Assets:
Total AFS securities	10,122		9,999
All other corporate [Member] | Level 3 [Member]
Assets:
Total AFS securities	295		236
Equity securities [Member]
Assets:
Total AFS securities	1,199		939
Equity securities [Member] | Level 1 [Member]
Assets:
Total AFS securities	953		781
Equity securities [Member] | Level 2 [Member]
Assets:
Total AFS securities	168		121
Equity securities [Member] | Level 3 [Member]
Assets:
Total AFS securities	78		37
Variable Annuity Assets (separate accounts) [Member]
Assets:
Variable annuity assets	608	[1]	580	[1]
Variable Annuity Assets (separate accounts) [Member] | Level 1 [Member]
Assets:
Variable annuity assets		[1]		[1]
Variable Annuity Assets (separate accounts) [Member] | Level 2 [Member]
Assets:
Variable annuity assets	608	[1]	580	[1]
Variable Annuity Assets (separate accounts) [Member] | Level 3 [Member]
Assets:
Variable annuity assets		[1]		[1]
Other Investments [Member]
Assets:
Other Investments	187		133
Other Investments [Member] | Level 1 [Member]
Assets:
Other Investments
Other Investments [Member] | Level 2 [Member]
Assets:
Other Investments	187		133
Other Investments [Member] | Level 3 [Member]
Assets:
Other Investments

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