Accounting policies - Investments (Details)	12 Months Ended
	Dec. 31, 2024
Accounting policies
Criteria for recognizing investment at cost	Investments where the Company does not exercise significant influence over the operating and financial policies of the investee and holds less than 20% of the voting stock are recorded at cost.
Equity method of accounting for investments, description	The Company uses the equity method of accounting for investments in common stock where the Company holds 20% to 50% of the voting stock of the investee and has significant influence over its operating and financial policies but does not meet the criteria for consolidation.