Investments (Mortgage Loans Modified in a Troubled Debt Restructuring) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Financing Receivable, Modifications [Line Items]
Number of Mortgage Loans	57	8	102	15
Carrying Value after Specific Valuation Allowance, Pre-Modification	$ 15	$ 74	$ 25	$ 79
Carrying Value after Specific Valuation Allowance, Post-Modification	13	74	21	79
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	0	0	0	0
Number of Mortgage Loans	0	1	0	1
Carrying Value after Specific Valuation Allowance, Pre-Modification	0	49	0	49
Carrying Value after Specific Valuation Allowance, Post-Modification	0	49	0	49
Agricultural [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	0	0	0	0
Number of Mortgage Loans	0	2	1	3
Carrying Value after Specific Valuation Allowance, Pre-Modification	0	24	1	28
Carrying Value after Specific Valuation Allowance, Post-Modification	0	24	1	28
Residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	2	0	4	0
Number of Mortgage Loans	57	5	101	11
Carrying Value after Specific Valuation Allowance, Pre-Modification	15	1	24	2
Carrying Value after Specific Valuation Allowance, Post-Modification	13	1	20	2
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0	$ 0	$ 1	$ 0

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953676-111524

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- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

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- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 34

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953682-111524

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Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

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