Investments and Derivative Instruments Level 4 Variable Interest Entities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Consolidated Variable Interest Entities [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$ 246	$ 199
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	6	33
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	245	177
Variable Interest Entity, Not Primary Beneficiary [Member]
Consolidated Variable Interest Entities [Abstract]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	3	3
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets	12	17
Variable Interest Entity, Nonconsolidated, Carrying Amount, Liabilities	14	19
Collateralized Debt Obligations [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Consolidated Variable Interest Entities [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	5	31
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	5	33
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	0	0
Fixed Income Funds [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Consolidated Variable Interest Entities [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	238	164
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	0	0
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	243	173
Limited Partnerships and Other Alternative Investments [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Consolidated Variable Interest Entities [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	3	4
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	1	0
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 2	$ 4

The carrying amount of the consolidated Variable Interest Entity's assets included in the reporting entity's statement of financial position.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (bb)

-URI http://asc.fasb.org/extlink&oid=28200181&loc=d3e5710-111685

+ Details

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- Definition

The carrying amount of the consolidated Variable Interest Entity's liabilities included in the reporting entity's statement of financial position.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph b

-URI http://asc.fasb.org/extlink&oid=28200181&loc=d3e5728-111685

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 6

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=28200181&loc=d3e5747-111685

+ Details

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Period Type:	instant

- Definition

Carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount of the liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

+ Details

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Balance Type:	credit
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- Details

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