Variable Interest Entities (Income Tax Credits and Other Tax Benefits and Amortization Expense) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Variable Interest Entity [Line Items]
Income Tax Credits and Other Income Tax Benefits	$ 27.7	$ 26.7
Amortization Expense	25.1	23.9
Affordable Housing
Variable Interest Entity [Line Items]
Income Tax Credits and Other Income Tax Benefits	24.0	21.7
Amortization Expense	21.6	19.5
New Markets
Variable Interest Entity [Line Items]
Income Tax Credits and Other Income Tax Benefits	3.7	5.0
Amortization Expense	$ 3.5	$ 4.4