Offsetting of Assets and Liabilities (Offsetting of Derivative Liabilities and Securities Sold Under Agreements to Repurchase) (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	$ 1,820.2	$ 4,841.3
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,444.5	4,199.6
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	375.7	641.7
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNT	375.7	641.7
Total Derivatives Not Subject to a Master Netting Arrangement
Total Derivatives Not Subject to a Master Netting Arrangement	634.9	317.1
Offsetting Derivative Liabilities [Abstract]
GROSS RECOGNIZED LIABILITIES	2,455.1	5,158.4
Derivative Liabilities	1,010.6	958.8
NET AMOUNT	1,010.6	958.8
Securities Sold under Agreements to Repurchase
GROSS RECOGNIZED LIABILITIES	65,268.1	65,374.8
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	64,896.6	64,912.8
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	371.5	462.0
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	371.5	462.0
NET AMOUNT	0.0	0.0
Foreign Exchange Contracts | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	1,551.9	4,392.7
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,414.3	4,197.3
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	137.6	195.4
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNT	137.6	195.4
Interest Rate Swap Contracts | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	249.3	421.2
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	12.4	2.3
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	236.9	418.9
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNT	236.9	418.9
Interest Rate Swap Contracts | Interest Rate Swaps Exchange Cleared
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES		0.2
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET		0.0
NET AMOUNTS PRESENTED IN THE BALANCE SHEET		0.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET		0.0
NET AMOUNT		0.2
Other Financial Derivatives | Other Financial Derivatives
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	19.0	27.2
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	17.8	0.0
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	1.2	27.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNT	$ 1.2	$ 27.2