Acquisitions - Schedule of Acquired Loans not Deemed to Have Credit Impairment (Details) $ in Millions	Feb. 01, 2022 USD ($)
Business Acquisition [Line Items]
Purchase price (initial fair value)	$ 623.3
Allowance for credit losses	298.2
Great Western Bank
Business Acquisition [Line Items]
Unpaid principal balance	979.2
Principal amounts previously written off by GWB	(238.7)
Interest applied to principal by GWB	(18.1)
Adjusted unpaid principal balance	722.4
Credit discount	(69.2)
Discount attributable to other factors	(29.9)
Purchase price (initial fair value)	623.3
Allowance for credit losses	59.5
Amortized cost basis	682.8
Unpaid principal balance	7,107.9
Credit discount (1)	(76.5)
Non-credit discount	(9.2)
Fair value	7,022.2
Amortized cost basis	$ 7,705.0