Capital management (Details)	Sep. 30, 2026	Dec. 31, 2025
Capital management
Total equity in % of total assets (equity ratio)	43.70%	46.10%
Debt and lease liabilities in % of total assets	34.60%	34.80%

Represents the percentage of debt and lease liabilities to total assets.

No definition available.

Name:	fms_PercentageOfDebtAndLeaseLiabilitiesToTotalAssets
Namespace Prefix:	fms_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant