Policyholders' Liabilities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Liability for Future Policy Benefit, by Product Segment [Line Items]
Individual and group annuities and supplementary contracts future policy benefits	24,840	19,046
net unrealized gains on securities classified as available for sale	14,745	8,412	1,656
Unpaid Claims And Claim Adjustment Expenses Interest Rate Lower End	0.00%
Unpaid Claims And Claim Adjustment Expenses Interest Rate High End	6.40%
Policyholders' account balances	134,552	106,441
Other Than Interest Sensitive Life Interest Rate Assumptions Low End	0.00%
Other Than Interest Sensitive Life Interest Rate Assumptions High End	13.40%
Interest Sensitive Life, Interest Rate Assumptions, Low End	0.00%
Interest Sensitive Life, Interest Rate Assumptions, High End	10.00%
Percentage Of Policyholders Account Balances With Interest Crediting Rates In Excess Of 8 Percent	1.00%
Premium Deficiency Reserves [Member]
Liability for Future Policy Benefit, by Product Segment [Line Items]
Individual and group annuities and supplementary contracts future policy benefits	2,447	2,001
net unrealized gains on securities classified as available for sale	1,432	926
Individual Participating Traditional Life Insurance [Member]
Liability for Future Policy Benefit, by Product Segment [Line Items]
Traditional life insurance low limit guaranteed mortality and nonforfeiture interest rate used to calculate future policy benefits	2.50%
Traditional life insurance high limit guaranteed mortality and nonforfeiture interest rate used to calculate future policy benefits	7.50%
Participating Policies As Percentage Of Direct Gross Life Insurance In Force	5.00%	6.00%
Participating Policies As Percentage Of Direct Gross Life Premiums	17.00%	24.00%	28.00%
Individual Non Participating Life Insurance Long Term Care And Individual Health [Member]
Liability for Future Policy Benefit, by Product Segment [Line Items]
Future Policy Benefits Interest Rate Low End	1.00%
Future Policy Benefits Interest Rate High End	15.00%
Percentage Of Reserves Based On Interest Rates In Excess Of 8 Percent	1.00%
Individual And Group Annuities And Supplementary Contracts [Member]
Liability for Future Policy Benefit, by Product Segment [Line Items]
Future Policy Benefits Interest Rate Low End	1.00%
Future Policy Benefits Interest Rate High End	11.90%
Percentage Of Reserves Based On Interest Rates In Excess Of 8 Percent	1.00%
Other Contract Liabilities [Member]
Liability for Future Policy Benefit, by Product Segment [Line Items]
Future Policy Benefits Interest Rate Low End	0.10%
Future Policy Benefits Interest Rate High End	6.00%
Funding Agreement Notes Issuance Program [Member]
Liability for Future Policy Benefit, by Product Segment [Line Items]
Policyholders' account balances	3,244	3,592
Other Than Interest Sensitive Life Interest Rate Assumptions Low End	0.50%
Other Than Interest Sensitive Life Interest Rate Assumptions High End	5.50%