Other Insurance Liabilities and Separate Accounts - Weighted-average Interest Rates and Durations (Details)	Mar. 31, 2025	Mar. 31, 2024
Large Case Pensions
Liability for Future Policy Benefit, Activity [Line Items]
Interest accretion rate	4.20%	4.20%
Current discount rate	5.31%	5.22%
Weighted-average duration of long-duration insurance liabilities	7 years 3 months 18 days	7 years 3 months 18 days
Long-Term Care
Liability for Future Policy Benefit, Activity [Line Items]
Interest accretion rate	5.11%	5.11%
Current discount rate	5.60%	5.36%
Weighted-average duration of long-duration insurance liabilities	11 years 7 months 6 days	12 years