Pledged and Restricted Assets - Accepted Collateral (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Total Collateral Accepted(2)	$ 12,574.4	$ 2,109.8
Fair value of securities received as collateral that have been resold or repledged	11,500.0	1,400.0
Reverse repurchase agreements
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Collateral that may be repledged or sold	12,119.4	1,457.0
Collateral that may not be repledged or sold	450.0	650.0
Derivative contracts
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Collateral that may be repledged or sold	$ 5.0	$ 2.8