Revenue from Contracts with Clients (Contract Receivables) (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Disaggregation of Revenue [Line Items]
Total Client Receivables	$ 1,077.2	$ 1,062.3
Trust Fees Receivable, net
Disaggregation of Revenue [Line Items]
Total Client Receivables	984.1	956.7
Fee receivable allowance	6.5	5.0
Other
Disaggregation of Revenue [Line Items]
Total Client Receivables	$ 93.1	$ 105.6