Goodwill and Other Intangibles (Goodwill by Reporting Segment) (Details) $ in Millions	6 Months Ended
Jun. 30, 2025 USD ($)
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 694.9
Foreign Exchange Rates	19.7
Goodwill, Ending Balance	714.6
ASSET SERVICING
Goodwill [Roll Forward]
Goodwill, Beginning Balance	614.6
Foreign Exchange Rates	19.6
Goodwill, Ending Balance	634.2
WEALTH MANAGEMENT
Goodwill [Roll Forward]
Goodwill, Beginning Balance	80.3
Foreign Exchange Rates	0.1
Goodwill, Ending Balance	$ 80.4

Amount, after accumulated impairment loss, of asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized.

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+ Details