Reporting Segments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Net Interest Income	$ 562.3	$ 456.2	$ 1,613.3	$ 1,498.9
Scenario, Adjustment | Asset Servicing segment
Segment Reporting Information [Line Items]
Net Interest Income	(36.0)		(99.0)
Scenario, Adjustment | Wealth Management segment
Segment Reporting Information [Line Items]
Net Interest Income	$ 36.0		$ 99.0