Derivative Instruments (Hedges of Net Investments in Foreign Operations) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Foreign Currency Forwards
Derivatives, Fair Value [Line Items]
Net Derivatives Gains (Losses) Deferred in AOCI	$ (106)	$ 11	$ (121)	$ 36

The current period gain (loss) recognized in other comprehensive income related to the effective portion of derivatives designated in cash flow hedges.

No definition available.

Name:	rga_GainsLossesDeferredInAccumulatedOtherComprehensiveIncomeLossOnDerivativesEffectivePortion
Namespace Prefix:	rga_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration