Reinsurance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Life insurance in-force
Written and earned direct	$ 96,428,523	$ 95,259,051
Reinsurance ceded	(11,401,557)	(10,563,137)
Reinsurance assumed	56,165,011	58,742,234
Net	$ 141,191,977	$ 143,438,148
Percentage of amount assumed to net	40.00%	41.00%
Premium income
Net	$ 465,349	$ 445,550	$ 446,395
Individual
Life insurance in-force
Written and earned direct	54,618,888	53,403,194
Reinsurance ceded	(10,568,467)	(10,169,625)
Reinsurance assumed	56,165,011	58,742,234
Net	$ 100,215,432	$ 101,975,803
Percentage of amount assumed to net	56.00%	58.00%
Group
Life insurance in-force
Written and earned direct	$ 41,809,635	$ 41,855,857
Reinsurance ceded	(833,090)	(393,512)
Reinsurance assumed	0	0
Net	$ 40,976,545	$ 41,462,345
Percentage of amount assumed to net	0.00%	0.00%
Life insurance
Premium income
Written and earned direct	$ 392,654	$ 368,442	360,959
Reinsurance ceded	(52,397)	(48,107)	(45,925)
Reinsurance assumed	123,175	124,798	130,201
Net	463,432	445,133	445,235
Annuities
Premium income
Written and earned direct	1,998	503	1,255
Reinsurance ceded	(81)	(86)	(95)
Net	1,917	417	1,160
Premium Income
Premium income
Written and earned direct	394,652	368,945	362,214
Reinsurance ceded	(52,478)	(48,193)	(46,020)
Reinsurance assumed	123,175	124,798	130,201
Net	$ 465,349	$ 445,550	$ 446,395