Consolidated Reinsurance (Consolidated Reinsurance) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount	$ 2,935,363us-gaap_LifeInsuranceInForceGross	$ 2,940,853us-gaap_LifeInsuranceInForceGross	$ 2,914,815us-gaap_LifeInsuranceInForceGross
Ceded	372,886us-gaap_LifeInsuranceInForceCeded	401,576us-gaap_LifeInsuranceInForceCeded	417,026us-gaap_LifeInsuranceInForceCeded
Assumed	830,980us-gaap_LifeInsuranceInForceAssumed	844,946us-gaap_LifeInsuranceInForceAssumed	785,391us-gaap_LifeInsuranceInForceAssumed
Net Amount	3,393,457us-gaap_LifeInsuranceInForceNet	3,384,223us-gaap_LifeInsuranceInForceNet	3,283,180us-gaap_LifeInsuranceInForceNet
% Amount Assumed to Net	24.50%	25.00%	23.90%
Consolidated Reinsurance
Gross Amount	20,963us-gaap_DirectPremiumsEarned	20,290us-gaap_DirectPremiumsEarned	19,821us-gaap_DirectPremiumsEarned
Ceded	1,252us-gaap_CededPremiumsEarned	1,284us-gaap_CededPremiumsEarned	1,291us-gaap_CededPremiumsEarned
Assumed	1,673us-gaap_AssumedPremiumsEarned	1,469us-gaap_AssumedPremiumsEarned	1,350us-gaap_AssumedPremiumsEarned
Net premiums	21,384us-gaap_PremiumsEarnedNet	20,475us-gaap_PremiumsEarnedNet	19,880us-gaap_PremiumsEarnedNet
% Amount Assumed to Net	7.80%us-gaap_PremiumsPercentageAssumedToNet	7.20%us-gaap_PremiumsPercentageAssumedToNet	6.80%us-gaap_PremiumsPercentageAssumedToNet
Life insurance (1)
Consolidated Reinsurance
Gross Amount	14,135	13,820	18,982
Ceded	1,159	1,187	756
Assumed	1,630	1,423	794
Net premiums	14,606	14,056	19,020
% Amount Assumed to Net	11.20%	10.10%	4.20%
Accident and health insurance
Consolidated Reinsurance
Gross Amount	6,828	6,470	839
Ceded	93	97	535
Assumed	43	46	556
Net premiums	$ 6,778	$ 6,419	$ 860
% Amount Assumed to Net	0.60%	0.70%	64.70%

Amount of earned premiums assumed from other entities.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 17

-Article 12

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 235

-Section S99

-Paragraph 2

-Subparagraph (SX 210.12-17)

-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.1)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 605

-Section 50

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-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

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Amount of earned premiums ceded to other entities.

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Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums earned.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 17

-Article 12

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 235

-Section S99

-Paragraph 2

-Subparagraph (SX 210.12-17)

-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.1)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 1

-Article 7

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 605

-Section 50

-Paragraph 1

-Subparagraph (b),(c)(1)

-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

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Amount of life insurance issued and outstanding assumed from other entities. Includes, but not limited to, dividends and adjustments to face value.

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- Definition

Amount of life insurance issued and outstanding ceded to other entities. Includes, but not limited to, dividends and adjustments to face value.

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Amount before contracts ceded to other entities and contracts assumed by the entity of life insurance issued and outstanding. Includes, but not limited to, dividends and adjustments to face value.

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Amount after contracts ceded to other entities and contracts assumed by the entity of life insurance issued and outstanding. Includes, but not limited to, dividends and adjustments to face value.

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Percentage of assumed life insurance issued and outstanding contracts to life insurance issued and outstanding after contracts ceded to other entities and contracts assumed by the entity. Includes, but not limited to, dividends and adjustments to face value.

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Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums earned.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 17

-Article 12

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 235

-Section S99

-Paragraph 2

-Subparagraph (SX 210.12-17)

-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.1)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 1

-Article 7

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 605

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.13(c))

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

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Percentage of assumed premiums earned by the entity to net premiums earned.

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