Reserve for Future Policy Benefits and Contractholder Funds - Schedule of Key Assumptions used in Calculating the Reserve for Future Policy Benefits (Details)	Mar. 31, 2024	Mar. 31, 2023
Accident and health insurance
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average duration (in years)	4 years 3 months 18 days	4 years 1 month 6 days
Interest accretion rate (discount rate at contract issuance)	4.96%	5.09%
Current discount rate (upper-medium grade fixed income yield)	5.02%	4.58%
Traditional life
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average duration (in years)	15 years 1 month 6 days	14 years 1 month 6 days
Interest accretion rate (discount rate at contract issuance)	5.41%	5.50%
Current discount rate (upper-medium grade fixed income yield)	5.35%	5.03%