Fair Value Disclosures (Narrative) (USD $)			3 Months Ended	9 Months Ended
Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Impaired commercial mortgages [Member]	Sep. 30, 2011 Impaired commercial mortgages [Member]	Sep. 30, 2012 Impaired commercial mortgages [Member]	Sep. 30, 2011 Impaired commercial mortgages [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Percentage Of Fixed Maturity Securities Classified As Level 3	9.10%	8.50%
Fair Value Measured On Nonrecurring Basis Gains (Losses)			$ 1,600,000	$ 1,900,000	$ 4,400,000	$ 1,500,000
Commercial Mortgage Loans Carrying Value Non Recurring			$ 23,500,000	$ 21,900,000	$ 23,500,000	$ 21,900,000

Carrying value of commercial mortgage loans where a nonrecurring fair value adjustment has been made, based on discounted cash flows using the market rate.

No definition available.

Name:	rga_CommercialMortgageLoansCarryingValueNonRecurring
Namespace Prefix:	rga_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant