Reinsurance (Income Statement Reinsurance Results) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Premiums:
Direct	$ 403,893	$ 379,576	$ 1,203,591	$ 1,129,131
Assumed	142	0	291	0
Ceded	(375,020)	(359,255)	(2,009,044)	(1,069,691)
Net premiums	29,015	20,321	(805,162)	59,440
Policy charges and fee income:
Direct	753,980	759,102	2,038,611	2,182,915
Assumed	112,825	179,717	417,048	336,672
Ceded	(778,326)	(392,475)	(1,781,686)	(903,610)
Net policy charges and fee income	88,479	546,344	673,973	1,615,977
Net investment income
Direct	104,448	102,847	290,104	309,201
Assumed	356	354	1,051	1,047
Ceded	(1,061)	(986)	(3,341)	(3,127)
Net investment income	103,743	102,215	287,814	307,121
Asset administration fees:
Direct	80,474	84,814	229,865	285,866
Assumed	0	0	0	0
Ceded	(76,470)	0	(149,466)	0
Net asset administration fees	4,004	84,814	80,399	285,866
Other income:
Direct	15,572	8,138	39,344	33,289
Assumed	(168)	0	216	0
Ceded	32	0	27	0
Amortization of reinsurance income	0	3,576	(19,228)	10,655
Net other income	15,436	11,714	20,359	43,944
Interest credited to policyholders’ account balances:
Direct	41,888	182,788	360,999	398,983
Assumed	33,662	31,541	99,080	93,155
Ceded	(33,469)	(57,843)	(203,591)	(169,932)
Net interest credited to policyholders’ account balances	42,081	156,486	256,488	322,206
Policyholders’ benefits (including change in reserves):
Direct	1,009,176	549,194	1,805,942	1,513,593
Assumed	181,318	208,099	653,892	431,184
Ceded	(1,135,998)	(642,107)	(2,777,218)	(1,710,827)
Policyholder Benefits and Claims Incurred, Net	54,496	115,186	(317,384)	233,950
Realized investment gains (losses), net:
Direct	383,846	(2,149,496)	(2,378,582)	18,471
Assumed	0	0	0	0
Ceded	(393,514)	2,146,512	3,284,527	(133,086)
Total realized investment gains (losses), net	(9,668)	(2,984)	905,945	(114,615)
Net reinsurance expense allowances, net of capitalization and amortization	(109,108)	(62,043)	(682,124)	(146,561)
Unaffiliated activity
Premiums:
Assumed	100		300
Policy charges and fee income:
Ceded	(4,000)	(4,000)	(4,000)	(4,000)
Other income:
Assumed	(200)	(100)	200	(100)
Policyholders’ benefits (including change in reserves):
Assumed	(200)
Ceded	(2,000)	(19,000)	4,000	(15,000)
Realized investment gains (losses), net:
Ceded	$ (5,000)	$ 12,000	$ 41,000	$ 12,000