Future policy benefits (Weighted average interest rates) (Details) - Segment Life [Member]	Mar. 31, 2026	Mar. 31, 2025
Term Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Interest Accretion Rate	3.20%	3.00%
Current Discount Rate	6.10%	5.60%
Whole Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Interest Accretion Rate	3.60%	3.50%
Current Discount Rate	4.40%	4.00%
Accident and Health Insurance Product Line [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Interest Accretion Rate	4.30%	4.10%
Current Discount Rate	6.10%	5.70%
Insurance, Other
Liability for Future Policy Benefit, Activity [Line Items]
Interest Accretion Rate	3.30%	3.20%
Current Discount Rate	3.70%	3.60%