Future policy benefits (Weighted average interest rates) (Details) - Segment Life [Member]	Sep. 30, 2025	Sep. 30, 2024
Term Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Interest Accretion Rate	3.00%	3.00%
Current Discount Rate	5.70%	5.20%
Whole Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Interest Accretion Rate	3.40%	3.20%
Current Discount Rate	4.10%	4.10%
Accident and Health Insurance Product Line [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Interest Accretion Rate	4.20%	3.80%
Current Discount Rate	5.80%	5.80%
Insurance, Other
Liability for Future Policy Benefit, Activity [Line Items]
Interest Accretion Rate	3.30%	2.70%
Current Discount Rate	3.50%	3.80%