Schedule IV - Reinsurance (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Life insurance in force
Gross amount, Life insurance in force	$ 879,508	$ 781,053	$ 710,140
Ceded to other companies, Life insurance in force	58,133	59,003	48,702
Assumed from other companies, Life insurance in force	3,180	3,459	4,435
Net amount, Life Insurance In Force	824,555us-gaap_PremiumsNetLifeInsuranceInForce	725,509us-gaap_PremiumsNetLifeInsuranceInForce	665,873us-gaap_PremiumsNetLifeInsuranceInForce
Premiums:
Gross amount, premiums	27,215us-gaap_DirectPremiumsEarned	25,541us-gaap_DirectPremiumsEarned	23,014us-gaap_DirectPremiumsEarned
Ceded to other companies, premiums	603us-gaap_CededPremiumsEarned	543us-gaap_CededPremiumsEarned	468us-gaap_CededPremiumsEarned
Assumed from other companies, premiums	602us-gaap_AssumedPremiumsEarned	577us-gaap_AssumedPremiumsEarned	471us-gaap_AssumedPremiumsEarned
Net amount	27,214us-gaap_PremiumsEarnedNet	25,575us-gaap_PremiumsEarnedNet	23,017us-gaap_PremiumsEarnedNet
Percentage of amount assumed to net, premiums	2.20%us-gaap_PremiumsPercentageAssumedToNet	2.30%us-gaap_PremiumsPercentageAssumedToNet	2.00%us-gaap_PremiumsPercentageAssumedToNet
Percentage of amount assumed to net, Life insurance in force	0.40%	0.50%	0.70%
Life insurance and annuities [Member]
Premiums:
Gross amount, premiums	2,302	2,140	2,013
Ceded to other companies, premiums	320	279	268
Assumed from other companies, premiums	32	28	29
Net amount	2,014	1,889	1,774
Percentage of amount assumed to net, premiums	1.60%	1.50%	1.60%
Accident and health insurance [Member]
Premiums:
Gross amount, premiums	24,913	23,401	21,001
Ceded to other companies, premiums	283	264	200
Assumed from other companies, premiums	570	549	442
Net amount	$ 25,200	$ 23,686	$ 21,243
Percentage of amount assumed to net, premiums	2.30%	2.30%	2.10%

Amount of earned premiums assumed from other entities.

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-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

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

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

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-Publisher FASB

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

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-Article 12

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-Publisher FASB

-Name Accounting Standards Codification

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

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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-Publisher FASB

-Name Accounting Standards Codification

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-Name Accounting Standards Codification

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