Offsetting of Assets and Liabilities - Offsetting of Derivative Liabilities and Securities Sold Under Agreements to Repurchase (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	$ 1,371.1	$ 4,841.3
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,175.7	4,199.6
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	195.4	641.7
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
Derivative Liabilities	195.4	641.7
Total Derivatives Not Subject to a Master Netting Arrangement
Total Derivatives Not Subject to a Master Netting Arrangement	1,038.5	317.1
Total Derivatives
GROSS RECOGNIZED LIABILITIES	2,409.6	5,158.4
Derivative Liabilities	1,233.9	958.8
NET AMOUNT	1,233.9	958.8
Securities Sold under Agreements to Repurchase
GROSS RECOGNIZED LIABILITIES	90,307.8	65,374.8
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	90,015.6	64,912.8
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	292.2	462.0
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	292.2	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	1,334.8	4,392.7
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,139.4	4,197.3
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	195.4	195.4
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
Derivative Liabilities	195.4	195.4
Interest Rate Swaps | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	5.0	421.2
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	5.0	2.3
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	0.0	418.9
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
Derivative Liabilities	0.0	418.9
Interest Rate Swaps | Interest Rate Swaps Exchange Cleared
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	0.0	0.2
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	0.0	0.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
Derivative Liabilities	0.0	0.2
Other Financial Derivatives | Other Financial Derivatives
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	31.3	27.2
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	31.3	0.0
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	0.0	27.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
Derivative Liabilities	$ 0.0	$ 27.2