Deferred Policy Acquisition Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance, beginning of year	$ 5,129,931	$ 5,081,938	$ 5,045,025
Capitalization of commissions, sales and issue expenses	316,828	616,002	626,718
Amortization-Impact of assumption and experience unlocking and true-ups	130,652	112,039	276,743
Amortization-All other	(758,753)	(771,208)	(708,555)
Change in unrealized investment gains and losses	(28,723)	91,160	(67,056)
Other	(3,448,842)	0	(90,937)
Balance, end of year	$ 1,341,093	$ 5,129,931	$ 5,081,938