Acquisitions and dispositions (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
Mar. 31, 2025	Sep. 30, 2025
Business Combination [Line Items]
Contingent consideration payable		$ 0
Increase (decrease) in contingent consideration liability		(5)
Contingent consideration receivable		5
Contingent receipts		6
Increase (decrease) in contingent consideration receivable		(2)
Dispositions		$ 18
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| BNY Trust Company of Canada
Business Combination [Line Items]
Gain from sale of business	$ 40
Dispositions	$ 18

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