Deposits - Scheduled Maturity of Total Time Deposits (Details) $ in Millions	Dec. 31, 2023 USD ($)
Time Deposits [Line Items]
1 Year or Less	$ 5,974.1
Over 1 Year to 2 Years	39.3
Over 2 Years to 3 Years	6.7
Over 3 Years to 4 Years	2.1
Over 4 Years to 5 Years	9.9
Over 5 Years	0.0
Total	6,032.1
U.S. OFFICE
Time Deposits [Line Items]
1 Year or Less	3,394.0
Over 1 Year to 2 Years	39.3
Over 2 Years to 3 Years	6.7
Over 3 Years to 4 Years	2.1
Over 4 Years to 5 Years	9.9
Over 5 Years	0.0
Total	3,452.0
NON-U.S. OFFICES
Time Deposits [Line Items]
1 Year or Less	2,580.1
Over 1 Year to 2 Years	0.0
Over 2 Years to 3 Years	0.0
Over 3 Years to 4 Years	0.0
Over 4 Years to 5 Years	0.0
Over 5 Years	0.0
Total	$ 2,580.1