Reinsurance (Balance Sheet Reinsurance Results) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Effects of Reinsurance [Line Items]
Reinsurance recoverables	$ 588,608	$ 3,088,328
Deferred policy acquisition costs	4,344,361	749,302	$ 1,114,431	$ 1,345,504
Deferred sales inducements	978,823	452,752	665,207	809,247
Value of business acquired	30,287	33,640	$ 39,738	$ 43,500
Other assets	169,649	123,158
Policyholders’ account balances	4,736,889	2,416,125
Future policy benefits	8,686,196	3,578,662
Reinsurance payable	275,822	250,277
Other liabilities	489,007	100,401
Impacts of Reinsurance
Effects of Reinsurance [Line Items]
Reinsurance recoverables	588,608	3,088,328
Deferred policy acquisition costs	3,557,248	(73,864)
Deferred sales inducements	520,182	(39,253)
Value of business acquired	(2,357)	(2,632)
Other assets	112,802	0
Policyholders’ account balances	2,576,357	0
Future policy benefits	5,130,753	0
Reinsurance payable	275,822	250,277
Other liabilities	335,713	0
Unaffiliated activity
Effects of Reinsurance [Line Items]
Reinsurance payable	$ 100	$ 200