Collateral Finance and Securitization Notes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2006
Collateral Finance Facility [Line Items]
Debt Instrument, Face Amount				$ 850,000,000.0
Direct investment in subsidiary				$ 112,800,000
Assets Held-in-trust	$ 841,500,000	$ 893,800,000
Amount Held In Debt Service Coverage Account	39,700,000	24,100,000
Collateral Financing Expense	28,636,000	25,827,000	$ 22,644,000
Debt Issuance Cost	20,405,000	22,218,000
RGA Americas [Member]
Collateral Finance Facility [Line Items]
Debt Issuance Cost	2,400,000
Reinsurance Group Of America Barbados [Member]
Collateral Finance Facility [Line Items]
Collateral Financing Expense	$ 4,200,000	4,000,000	2,300,000
Timerberlake Financial [Member]
Collateral Finance Facility [Line Items]
Debt Instrument, Issuance Date	Jun. 01, 2006
Collateral Financing Expense	$ 6,400,000	4,200,000	3,800,000
RGA Barbados [Member]
Collateral Finance Facility [Line Items]
Debt Issuance Cost	1,300,000
Chesterfield Financial Holdings LLC [Member]
Collateral Finance Facility [Line Items]
Debt Instrument, Face Amount	300,000,000.0
Assets Held-in-trust	19,400,000	22,100,000
Collateral Financing Expense	11,300,000	$ 13,100,000	$ 14,000,000
Debt Issuance Cost	$ 5,400,000
Debt Instrument, Interest Rate, Stated Percentage	4.50%
Minimum [Member]
Collateral Finance Facility [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	$ 35,000,000