Reserve for Future Policy Benefits and Contractholder Funds - Schedule of Key Assumptions used in Calculating the Reserve for Future Policy Benefits (Details)	Mar. 31, 2025	Mar. 31, 2024
Accident and health insurance
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average duration (in years)	7 years 9 months 18 days	4 years 3 months 18 days
Weighted-average interest rates
Interest accretion rate (discount rate at contract issuance)	5.10%	4.96%
Current discount rate (upper-medium grade fixed income yield)	5.26%	5.02%
Traditional life
Liability for Future Policy Benefit, Activity [Line Items]
Weighted-average duration (in years)	15 years 1 month 6 days	15 years 1 month 6 days
Weighted-average interest rates
Interest accretion rate (discount rate at contract issuance)	5.37%	5.41%
Current discount rate (upper-medium grade fixed income yield)	5.46%	5.35%