Reinsurance (Reinsurance amounts included in the Statements of Financial Position) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Effects of Reinsurance [Line Items]
Reinsurance recoverables	$ 567,185	$ 694,040
Deferred policy acquisition costs	4,214,451	4,237,780
Deferred sales inducements	692,177	714,598
Value of business acquired	28,479	27,247
Other assets	543,529	767,540
Policyholders’ account balances	12,617,404	9,181,459
Reinsurance payables	147,807	178,860
Other liabilities	805,037	980,692
Impacts of Reinsurance
Effects of Reinsurance [Line Items]
Reinsurance recoverables	567,185	694,040
Deferred policy acquisition costs	3,231,384	3,414,620
Deferred sales inducements	361,178	374,631
Value of business acquired	(2,170)	(2,124)
Other assets	57,701	61,471
Policyholders’ account balances	3,199,407	3,273,863
Future policy benefits	9,047,794	12,610,942
Reinsurance payables	147,807	178,860
Other liabilities	244,944	262,462
Unaffiliated activity
Effects of Reinsurance [Line Items]
Reinsurance payables	$ 1,300	$ 2,300