Reserve for Life-Contingent Contract Benefits and Contractholder Funds (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	$ 14,406	$ 13,450
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Premium deficiency reserve	(594)	(9)
Structured settlement annuities
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	7,075	6,500
Structured settlement annuities \| Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	9.30%
Structured settlement annuities \| Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	0.00%
Other immediate fixed annuities
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	2,350	2,205
Other immediate fixed annuities \| Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	11.50%
Other immediate fixed annuities \| Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	0.90%
Traditional life insurance
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	3,004	2,938
Traditional life insurance \| Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	11.30%
Traditional life insurance \| Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	4.00%
Accident and health insurance
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	1,859	1,720
Accident and health insurance \| Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	5.30%
Accident and health insurance \| Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	3.00%
Other
Reserve for life-contingent benefits:
Total reserve for life-contingent contract benefits	$ 118	$ 87
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Percentage of Annuity 2000 mortality table rate used in calculating the reserve for variable annuity guaranteed minimum death benefits	100.00%
Other \| Maximum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	5.10%
Other \| Minimum
Key assumptions generally used in calculating the reserve for life-contingent contract benefits:
Life contingent contract benefits, interest rate assumptions (as a percent)	4.00%

The sum of the known and estimated amounts payable as of the balance sheet date to policyholders pertaining to insured events for long-duration contracts, which can be viewed as either (a) the present value of future benefits to be paid to or on behalf of policyholders and expenses less the present value of future net premiums payable under the insurance contracts or (b) the accumulated amount of net premiums already collected less the accumulated amount of benefits and expenses already paid to or on behalf of policyholders.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 7

-Section 03

-Paragraph 13

-Subparagraph a

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 40

-Section 25

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=6482067&loc=d3e13145-158430

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 97

-Paragraph 15-21

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.13(a)(1))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 113

-Paragraph 26

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 60

-Paragraph 21-26

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details