Future Contract Benefits - Summary of Changes in Present Values of LFPB (Group Protection) (Details) - Group Protection - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025	Dec. 31, 2024
Present Value of Expected Future Policy Benefits
Balance as of beginning-of-year	$ 5,836	$ 5,628
Effect of cumulative changes in discount rate assumptions			$ (363)	$ (550)
Beginning balance at original discount rate	6,199	6,178
Effect of actual variances from expected experience			$ (47)	$ (72)
Adjusted balance as of beginning-of-year	6,152	6,106
Issuances	377	402
Interest accrual	55	50
Benefit payments	(380)	(371)
Ending balance at original discount rate	6,204	6,187
Effect of cumulative changes in discount rate assumptions	(411)	(475)
Balance as of end-of-period	5,793	5,712
Less: Reinsurance recoverables	123	121
Net balance as of end-of-period, net of reinsurance	$ 5,670	$ 5,591
Weighted-average duration of future policyholder benefit liability	5 years	5 years