Schedule IV - Reinsurance (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reinsurance [Line Items]
Life insurance in force, gross	$ 97,410,319us-gaap_LifeInsuranceInForceGross	$ 98,596,728us-gaap_LifeInsuranceInForceGross	$ 98,994,909us-gaap_LifeInsuranceInForceGross
Life insurance in force, ceded to other companies	29,365,216us-gaap_LifeInsuranceInForceCeded	34,445,475us-gaap_LifeInsuranceInForceCeded	29,266,410us-gaap_LifeInsuranceInForceCeded
Life insurance in force, assumed other companies	1,642,259us-gaap_LifeInsuranceInForceAssumed	8,162,720us-gaap_LifeInsuranceInForceAssumed	8,009,353us-gaap_LifeInsuranceInForceAssumed
Life insurance in force, net	69,687,362us-gaap_LifeInsuranceInForceNet	72,313,973us-gaap_LifeInsuranceInForceNet	77,737,852us-gaap_LifeInsuranceInForceNet
Life insurance in force, percentage of amount assumed to net	2.40%	11.30%	10.30%
Premiums, direct amount	11,250,949us-gaap_DirectPremiumsEarned	9,848,656us-gaap_DirectPremiumsEarned	9,279,927us-gaap_DirectPremiumsEarned
Premiums, ceded to other companies	3,106,463us-gaap_CededPremiumsEarned	2,403,957us-gaap_CededPremiumsEarned	2,333,639us-gaap_CededPremiumsEarned
Premiums, assumed from other companies	487,656us-gaap_AssumedPremiumsEarned	315,097us-gaap_AssumedPremiumsEarned	290,696us-gaap_AssumedPremiumsEarned
Net earned premiums	8,632,142us-gaap_PremiumsEarnedNet	7,759,796us-gaap_PremiumsEarnedNet	7,236,984us-gaap_PremiumsEarnedNet
Premiums, percentage of amount assumed to net	5.60%us-gaap_PremiumsPercentageAssumedToNet	4.10%us-gaap_PremiumsPercentageAssumedToNet	4.00%us-gaap_PremiumsPercentageAssumedToNet
Direct policyholder benefits	6,947,121	4,639,958	5,061,922
Benefits, ceded to other companies	2,872,064	1,198,716	1,607,780
Benefits, assumed from other companies	330,276	234,290	201,262
Net policyholder benefits	4,405,333	3,675,532	3,655,404
Benefits, percentage of amount assumed to net	7.50%	6.40%	5.50%
Life insurance
Reinsurance [Line Items]
Premiums, direct amount	720,478	729,519	761,358
Premiums, ceded to other companies	361,860	373,641	383,099
Premiums, assumed from other companies	27,588	39,218	37,730
Net earned premiums	386,206	395,096	415,989
Premiums, percentage of amount assumed to net	7.10%	9.90%	9.10%
Direct policyholder benefits	736,430	736,349	737,543
Benefits, ceded to other companies	364,064	361,592	371,629
Benefits, assumed from other companies	23,812	27,262	29,007
Net policyholder benefits	396,178	402,019	394,921
Benefits, percentage of amount assumed to net	6.00%	6.80%	7.30%
Accident and health insurance
Reinsurance [Line Items]
Premiums, direct amount	3,429,376	3,089,192	3,139,487
Premiums, ceded to other companies	629,062	674,640	684,302
Premiums, assumed from other companies	175,768	170,848	177,755
Net earned premiums	2,976,082	2,585,400	2,632,940
Premiums, percentage of amount assumed to net	5.90%	6.60%	6.80%
Direct policyholder benefits	3,450,893	1,995,860	1,962,716
Benefits, ceded to other companies	1,410,856	345,806	319,062
Benefits, assumed from other companies	153,621	147,460	142,441
Net policyholder benefits	2,193,658	1,797,514	1,786,095
Benefits, percentage of amount assumed to net	7.00%	8.20%	8.00%
Property and liability insurance
Reinsurance [Line Items]
Premiums, direct amount	7,101,095	6,029,945	5,379,082
Premiums, ceded to other companies	2,115,541	1,355,676	1,266,238
Premiums, assumed from other companies	284,300	105,031	75,211
Net earned premiums	5,269,854	4,779,300	4,188,055
Premiums, percentage of amount assumed to net	5.40%	2.20%	1.80%
Direct policyholder benefits	2,759,798	1,907,749	2,361,663
Benefits, ceded to other companies	1,097,144	491,318	917,089
Benefits, assumed from other companies	152,843	59,568	29,814
Net policyholder benefits	$ 1,815,497	$ 1,475,999	$ 1,474,388
Benefits, percentage of amount assumed to net	8.40%	4.00%	2.00%

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Amount of earned premiums assumed from other entities.

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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.

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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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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, before effect of policies assumed or ceded, of expense related to provision for policy benefits and costs incurred.

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Amount, after effects of policies assumed or ceded, of expense related to the provision for policy benefits and costs incurred.

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

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

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Amount of policy benefits and costs incurred for policies assumed.

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Amount of reduction of provision for policy benefits and costs incurred for policies ceded.

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