Revenue from Contracts with Clients (Contract Receivables) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total Client Receivables	$ 1,096.6	$ 1,052.1
Trust Fees Receivable, net
Disaggregation of Revenue [Line Items]
Total Client Receivables	954.1	925.2
Contract with customer, asset, allowance for credit loss	14.9	10.9
Other
Disaggregation of Revenue [Line Items]
Total Client Receivables	$ 142.5	$ 126.9