Schedule IV - Reinsurance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reinsurance [Line Items]
Life insurance in force, gross	$ 93,926,136	$ 97,410,319	$ 98,596,728
Life insurance in force, ceded to other companies	26,786,323	29,365,216	34,445,475
Life insurance in force, assumed other companies	1,397,236	1,642,259	8,162,720
Life insurance in force, net	$ 68,537,049	$ 69,687,362	$ 72,313,973
Life insurance in force, percentage of amount assumed to net	2.00%	2.40%	11.30%
Premiums, direct amount	$ 11,600,724	$ 11,250,949	$ 9,848,656
Premiums, assumed from other companies	525,988	487,656	315,097
Premiums, ceded to other companies	3,775,715	3,106,463	2,403,957
Net earned premiums	$ 8,350,997	$ 8,632,142	$ 7,759,796
Premiums, percentage of amount assumed to net	6.30%	5.60%	4.10%
Direct policyholder benefits	$ 6,962,357	$ 6,947,121	$ 4,639,958
Benefits, ceded to other companies	2,530,695	2,872,064	1,198,716
Benefits, assumed from other companies	310,873	330,276	234,290
Net policyholder benefits	$ 4,742,535	$ 4,405,333	$ 3,675,532
Benefits, percentage of amount assumed to net	6.60%	7.50%	6.40%
Life insurance
Reinsurance [Line Items]
Premiums, direct amount	$ 664,738	$ 720,478	$ 729,519
Premiums, assumed from other companies	16,788	27,588	39,218
Premiums, ceded to other companies	316,533	361,860	373,641
Net earned premiums	$ 364,993	$ 386,206	$ 395,096
Premiums, percentage of amount assumed to net	4.60%	7.10%	9.90%
Direct policyholder benefits	$ 667,984	$ 736,430	$ 736,349
Benefits, ceded to other companies	295,528	364,064	361,592
Benefits, assumed from other companies	20,008	23,812	27,262
Net policyholder benefits	$ 392,464	$ 396,178	$ 402,019
Benefits, percentage of amount assumed to net	5.10%	6.00%	6.80%
Accident and health insurance
Reinsurance [Line Items]
Premiums, direct amount	$ 3,677,759	$ 3,429,376	$ 3,089,192
Premiums, assumed from other companies	177,510	175,768	170,848
Premiums, ceded to other companies	630,083	629,062	674,640
Net earned premiums	$ 3,225,186	$ 2,976,082	$ 2,585,400
Premiums, percentage of amount assumed to net	5.50%	5.90%	6.60%
Direct policyholder benefits	$ 3,536,448	$ 3,450,893	$ 1,995,860
Benefits, ceded to other companies	774,591	1,410,856	345,806
Benefits, assumed from other companies	153,912	153,621	147,460
Net policyholder benefits	$ 2,915,769	$ 2,193,658	$ 1,797,514
Benefits, percentage of amount assumed to net	5.30%	7.00%	8.20%
Property and liability insurance
Reinsurance [Line Items]
Premiums, direct amount	$ 7,258,227	$ 7,101,095	$ 6,029,945
Premiums, assumed from other companies	331,690	284,300	105,031
Premiums, ceded to other companies	2,829,099	2,115,541	1,355,676
Net earned premiums	$ 4,760,818	$ 5,269,854	$ 4,779,300
Premiums, percentage of amount assumed to net	7.00%	5.40%	2.20%
Direct policyholder benefits	$ 2,757,925	$ 2,759,798	$ 1,907,749
Benefits, ceded to other companies	1,460,576	1,097,144	491,318
Benefits, assumed from other companies	136,953	152,843	59,568
Net policyholder benefits	$ 1,434,302	$ 1,815,497	$ 1,475,999
Benefits, percentage of amount assumed to net	9.50%	8.40%	4.00%