Guaranteed Minimum Death Benefit Contracts (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Guaranteed Minimum Death Benefit Contracts Reserve Strengthening [Abstract]
Pre Tax Guaranteed Benefits Reserve Strengthening	$ 43	$ 70	$ 52
After Tax Guaranteed Benefits Reserve Strengthening	27	45	34
Variable Annuity [Member] | Guaranteed Minimum Death Benefit [Member]
Guaranteed Minimum Death Benefits Account Value Risk And Average Age Table [Line Items]
Account value	13,303	13,753
Net amount at risk	4,018	5,377
Average attained age of contractholders (weighted by exposure)	72	71
Guaranteed Minimum Death Benefits Total Contractholders	435,000	480,000
Variable Annuity [Member] | Guaranteed Minimum Death Benefit [Member] | Highest Anniversary Annuity Value [Member]
Guaranteed Minimum Death Benefits Account Value Risk And Average Age Table [Line Items]
Account value	10,485	10,801
Net amount at risk	3,303	4,487
Average attained age of contractholders (weighted by exposure)	72	71
Variable Annuity [Member] | Guaranteed Minimum Death Benefit [Member] | Anniversary Value Reset [Member]
Guaranteed Minimum Death Benefits Account Value Risk And Average Age Table [Line Items]
Account value	1,183	1,184
Net amount at risk	22	56
Average attained age of contractholders (weighted by exposure)	65	63
Variable Annuity [Member] | Guaranteed Minimum Death Benefit [Member] | Other [Member]
Guaranteed Minimum Death Benefits Account Value Risk And Average Age Table [Line Items]
Account value	1,635	1,768
Net amount at risk	693	834
Average attained age of contractholders (weighted by exposure)	71	70
Variable Annuity [Member] | Guaranteed Minimum Death Benefit [Member]
Guaranteed Minimum Death Benefits Reserves [Line Items]
Future Policy Benefit Reserve, beginning balance, gross	1,170	1,138	1,285
Claims payable, beginning balance, gross	40	37	36
Less: Reinsurance and other amounts recoverable	53	51	53
Balance at January 1, net	1,157	1,124	1,268
Add: Incurred benefits	17	138	(20)
Less: Paid benefits	102	105	124
Ending balance, net	1,072	1,157	1,124
Claims payable, ending balance, gross	24	40	37
Add: Reinsurance and other amounts recoverable	42	53	51
Future Policy Benefit Reserve, ending balance, gross	$ 1,090	$ 1,170	$ 1,138
Variable Annuity [Member] | Guaranteed Minimum Death Benefit [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Partial Surrenders Estimate Annual Election Rate Low	0.00%
Partial Surrenders Estimate Annual Election Rate High	13.00%
Guaranteed Minimum Death Benefit Contracts Discount Rate	5.75%
Fund fees, low end	1.00%
Fund fees, high end	3.00%
Mortality Assumption as a Percentage of 1994 Group Annuity Mortality table, Low	65.00%
Mortality Assumption as a Percentage of 1994 Group Annuity Mortality table, High	89.00%
Annual percentage improvement in the mortality assumption percent	1.00%
Lapse Rate Assumption, Low	0.00%
Lapse Rate Assumption, High	11.00%
Variable Annuity [Member] | Guaranteed Minimum Death Benefit [Member] | Equity Funds [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Short Term Interest Rate Assumption For Future Periods	4.00%
Mean Investment Performance Assumption	4.00%	4.75%
Volatility Assumption Low	18.00%
Volatility Assumption High	24.00%
Variable Annuity [Member] | Guaranteed Minimum Death Benefit [Member] | Fixed Income Funds [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Mean Investment Performance Assumption	5.00%
Volatility Assumption Low	5.00%
Volatility Assumption High	7.00%
Variable Annuity [Member] | Guaranteed Minimum Death Benefit [Member] | Money Market Funds [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Volatility Assumption Low	0.00%
Volatility Assumption High	1.00%