Offsetting of Assets and Liabilities (Offsetting of Derivative Liabilities and Securities Sold Under Agreements to Repurchase) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	$ 2,063.0	$ 2,548.9
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,525.6	1,865.9
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	537.4	683.0
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
Net Amount	537.4	683.0
Total Derivatives Not Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	614.8	1,105.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0
NET AMOUNT	614.8	1,105.2
Offsetting Derivative Liabilities [Abstract]
GROSS RECOGNIZED LIABILITIES	2,677.8	3,654.1
Derivative Liabilities	1,152.2	1,788.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNT	1,152.2	1,788.2
Securities Sold under Agreements to Repurchase(2)
GROSS RECOGNIZED LIABILITIES	22,337.9	11,991.1
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	21,975.0	11,423.9
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	362.9	567.2
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	362.9	567.2
Other liabilities	3,600.0	3,200.0
Foreign Exchange Contracts | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	1,657.2	2,082.3
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	1,499.5	1,826.7
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	157.7	255.6
GROSS AMOUNTS NOT OFFSET IN THE BALANCE SHEET	0.0	0.0
Net Amount	157.7	255.6
Interest Rate Swap Contracts | Over the Counter Derivative
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	369.9	426.5
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	11.8	5.9
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	358.1	420.6
Net Amount	358.1	420.6
Interest Rate Swap Contracts | Interest Rate Swaps Exchange Cleared
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	0.0	5.3
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	0.0	0.0
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	0.0	5.3
Net Amount	0.0	5.3
Other Financial Derivatives | Other Financial Derivatives
Total Derivatives Subject to a Master Netting Arrangement
GROSS RECOGNIZED LIABILITIES	35.9	34.8
GROSS AMOUNTS OFFSET IN THE BALANCE SHEET	14.3	33.3
NET AMOUNTS PRESENTED IN THE BALANCE SHEET	21.6	1.5
Net Amount	$ 21.6	$ 1.5