Financing Activities (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2025 USD ($)	Jun. 30, 2025 USD ($)
Debt Instrument [Line Items]
Line of Credit Facility, Commitment Fee Amount		$ 1,000
Line of Credit Facility, Initiation Date		Jun. 04, 2025
Line of Credit Facility, Commitment Fee Percentage		6.722%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		1.789%
Line of Credit Facility, Description		On June 4, 2025, the Company entered into a 30-year facility agreement with a Delaware trust (the “Trust”) in connection with the sale by the Trust of $1.0 billion of pre-capitalized securities. The Trust invested the proceeds from the sale of its securities in a portfolio of principal and interest strips of U.S. Treasury securities.
Line of Credit Facility, Interest Rate Description		The facility agreement provides the Company with the right to issue and sell to the Trust from time to time up to $1.0 billion of its 6.722% senior notes due 2055 in exchange for a corresponding amount of the U.S. Treasury securities held by the Trust. In return, the Company agreed to pay a semi-annual facility fee to the Trust at a rate of 1.789% per year applied to the maximum amount of senior notes that the Company could issue to the Trust. The Company can redeem the 6.722% Senior Notes at any time, in whole or in part. At June 30, 2025, the Company had not issued any senior notes under the facility agreement.
Line of Credit Facility, Priority		The issuance right will be exercised automatically in full upon the Company’s failure to make certain payments to the Trust, or upon certain bankruptcy events involving RGA. The Company is also required to exercise the issuance right in full if its consolidated stockholders’ equity (excluding AOCI and noncontrolling interests) falls below a minimum threshold of $2.0 billion and upon certain other events described in the facility agreement.
Subordinated Debentures due 2055
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.65%	6.65%
Debt Instrument, Face Amount	$ 700	$ 700
Debt Related Commitment Fees and Debt Issuance Costs	$ 9