Fair Value (Carrying amount and estimated fair value of financial instrument assets and liabilities which are not measured at fair value) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Financial Assets [Abstract]
Notes receivable for the issuance of common stock	$ 20	$ 21
Mortgage loans	425	401
Financial Liabilities [Abstract]
Short term debt	13	13
Long term debt	2,558	2,557
Carrying Amount [Member]
Financial Assets [Abstract]
Notes receivable for the issuance of common stock	20	21
Mortgage loans	425	401
Financial Liabilities [Abstract]
Premium deposits and annuity contracts	96	100
Short term debt	13	13
Long term debt	2,558	2,557
Estimated Fair Value [Member]
Financial Assets [Abstract]
Notes receivable for the issuance of common stock	20	21
Mortgage loans	449	418
Financial Liabilities [Abstract]
Premium deposits and annuity contracts	100	104
Short term debt	13	13
Long term debt	3,016	3,016
Level 1 [Member] \| Estimated Fair Value [Member]
Financial Assets [Abstract]
Notes receivable for the issuance of common stock
Mortgage loans
Financial Liabilities [Abstract]
Premium deposits and annuity contracts
Short term debt
Long term debt
Level 2 [Member] \| Estimated Fair Value [Member]
Financial Assets [Abstract]
Notes receivable for the issuance of common stock
Mortgage loans
Financial Liabilities [Abstract]
Premium deposits and annuity contracts
Short term debt	13	13
Long term debt	3,016	3,016
Level 3 [Member] \| Estimated Fair Value [Member]
Financial Assets [Abstract]
Notes receivable for the issuance of common stock	20	21
Mortgage loans	449	418
Financial Liabilities [Abstract]
Premium deposits and annuity contracts	100	104
Short term debt
Long term debt

Premium deposits and annuity contracts

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19,20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19

-Article 5

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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- Definition

The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 60

-Paragraph 47

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(c))

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph c

-Article 7

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- Definition

Amounts receivable from officers and directors resulting from the sale of stock to officers or directors before the cash payment is received.

+ References

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 4

-Section E

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 30

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29,30)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 4.E)

-URI http://asc.fasb.org/extlink&oid=6228006&loc=d3e74512-122707

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