Certain Long-Duration Contracts With Guarantees (Changes in Deferred Sales Inducements, Reported as "Interest credited to policyholders' account balances") (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement in Deferred Sales Inducements [Roll Forward]
Balance, beginning of year	$ 836,791	$ 989,889	$ 787,891
Capitalization	6,462	9,112	20,871
Amortization-Impact of assumption and experience unlocking and true-ups	21,829	34,420	14,613
Amortization-All other	(183,843)	(194,673)	160,835
Change in unrealized investment gains (losses)	3,605	(1,957)	5,679
Balance, end of year	$ 684,844	$ 836,791	$ 989,889