Reinsurance (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Effects of Reinsurance [Line Items]
Maximum Life Insurance Retention Per Individual Life	$ 8,000
Reinsurance ceded receivables	782,027	$ 683,972
Reinsurance Claims Recoverables	243,800	242,000
Claims Recoverable From Retrocessionaires Past Due	1,900	4,000
Statutory Financial Reinsurance	16,200,000	10,800,000
Statutory Reserves Related To Financial Requirements	2,901,100	1,935,000
Assets Held-in-trust	841,500	893,800
Benefit Of RGA Subsidiaries [Member]
Effects of Reinsurance [Line Items]
Assets Held-in-trust	2,214,100	2,372,100
Benefit Of Third Parties [Member]
Effects of Reinsurance [Line Items]
Assets Held-in-trust	$ 15,584,300	$ 12,135,300
AM Best, A- Rating [Member]
Effects of Reinsurance [Line Items]
Retrocession Pool Participants Minimum AM Best Rating	“A- (excellent)”	“A- (excellent)”