Financial Condition and Net Income on a Statutory Basis - Significant Subsidiaries (Statutory Accounting Practices Disclosure) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
RGA Reinsurance [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance		$ 1,584,007	$ 1,521,644
Statutory Accounting Practices, Statutory Net Income Amount		138,359	148,576	$ (23,615)
RCM [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance		1,557,453	1,651,274
Statutory Accounting Practices, Statutory Net Income Amount		(183,136)	272,038	51,041
RGA Canada [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance		1,006,190	915,134
Statutory Accounting Practices, Statutory Net Income Amount		25,971	13,947	113,526
RGA Barbados [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	[1]	1,278,006	957,051
Statutory Accounting Practices, Statutory Net Income Amount	[1]	309,346	95,859	113,049
RGA Australia [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance		476,528	370,039
Statutory Accounting Practices, Statutory Net Income Amount		78,497	(7,694)	(18,128)
RGA Atlantic [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance		812,307	596,016
Statutory Accounting Practices, Statutory Net Income Amount		213,511	110,172	132,192
RGA Americas [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	[1]	4,833,890	3,752,910
Statutory Accounting Practices, Statutory Net Income Amount	[1]	624,145	282,226	264,518
Other Reinsurance Subsidiaries [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance		2,694,317	2,224,833
Statutory Accounting Practices, Statutory Net Income Amount		$ 65,658	$ 130,289	$ 300,847

[1] In 2017, the Company contributed to RGA Americas Reinsurance Company, Ltd. all of the outstanding shares of its wholly-owned subsidiary, RGA Australia. Periods prior to 2017 have been adjusted to reflect this contribution.