Financial Condition and Net Income on a Statutory Basis - Significant Subsidiaries (Narrative) (Details) $ in Millions	12 Months Ended
Dec. 31, 2017 USD ($)
Statutory Basis [Abstract]
Number Of Preceeding Months To Accumulate Dividend Paid For Approval	12 months
Future Dividend Payment Restricted To Such Percent Of Surplus To Policy Holders	10.00%
RGA Reinsurance Max Dividend Payments Without Approval	$ 158.4

The number of preceeding months used to determine the amount of allowable dividends paid to stockholders.

No definition available.

Name:	rga_NumberOfPreceedingMonthsToAccumulateDividendPaidForApproval
Namespace Prefix:	rga_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration