Goodwill and Other Intangibles (Other Intangible Assets and Capitalized Software) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Other Intangible Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 130.9	$ 135.0
Less: Accumulated Amortization	63.9	63.4
Net Book Value	67.0	71.6
Computer Software
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,905.3	3,781.7
Less: Accumulated Amortization	1,893.9	1,754.2
Net Book Value	$ 2,011.4	$ 2,027.5