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	$ 28,674,226	$ 22,691,491
Policy loans	(1,166,456)	(1,143,303)
Deferred policy acquisition costs	(1,341,093)	(5,129,931)	$ (5,081,938)	$ (5,045,025)
Deferred sales inducements	0	(684,844)	$ (836,791)	$ (989,889)
Other assets	279,222	59,578
Policyholders’ account balances		17,204,824
Future policy benefits		15,198,755
Other liabilities	849,698	935,662
Impacts of Reinsurance
Effects of Reinsurance [Line Items]
Reinsurance recoverables	28,674,226	22,691,491
Policy loans	(87,112)	(75,697)
Deferred policy acquisition costs	(6,482,889)	(2,158,121)
Deferred sales inducements	(615,117)	0
Other assets	226,347	35,616
Policyholders’ account balances	4,978,859	5,020,230
Future policy benefits	2,833,327	2,380,215
Other liabilities	410,376	516,525
Unaffiliated
Effects of Reinsurance [Line Items]
Other assets	100	0
Other liabilities	$ 28,000	$ 22,000