Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Stock Repurchase Program, Authorized Amount	$ 400.0		$ 400.0
Treasury Stock, Value, Acquired, Cost Method	81.0	$ 99.0	163.0
Proceeds from Issuance of Common Stock	$ 0.0	0.0	$ 481.0
Stock Issued During Period, Shares, New Issues			6,172,840
Shares Issued, Price Per Share			$ 81.00
Common stock par value	$ 0.01		$ 0.01
Common Stock Issued Underwriter Option			925,926
Common Stock Price Per Share Underwriter Option			$ 81.00
Stockholders' Equity Attributable to Noncontrolling Interest	$ 90.0	0.0	$ 0.0	$ 0.0
Net Income (Loss) Attributable to Noncontrolling Interest	$ 4.0	$ 0.0	$ 0.0
Noncontrolling Interest, Dividend Requirements of Preferred Stock	In 2022, Papara Financing LLC (“Papara”), a subsidiary of RGA Reinsurance, issued nonconvertible preferred interests to an unaffiliated third party. Papara holds investments in mortgage loans. The membership interests in Papara consist of (1) common interests, which are held by RGA Reinsurance and (2) preferred interests. The preferred interests total $90 million and pay an initial preferred distribution at an annual rate of 2.375% plus three month LIBOR. The applicable rate of interest is reset every five years. Distributions are paid quarterly, if declared by Papara. RGA can call the Papara preferred interests at the issue price beginning five years from the issuance date or upon the receipt of proceeds from the sale of the underlying assets. The holders of the Papara preferred interests have the option to require redemption upon the occurrence of certain contingent events, such as the failure of Papara to pay the preferred distribution for two or more periods or to meet certain other requirements, including a minimum credit rating. If notice is given upon such an event, all other holders of equal or more subordinate classes of membership interests in Papara are entitled to receive the same form of consideration payable to the holders of the preferred interests, resulting in a deemed liquidation for accounting purposes.