Acquisitions - Schedule of Acquired Loans not Deemed to Have Credit Impairment (Details) - USD ($) $ in Millions	Feb. 01, 2022	Mar. 31, 2022
Business Acquisition [Line Items]
Purchase price (initial fair value)	$ 606.9
Allowance for credit losses	323.0	$ 323.0
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	(90.9)
Discount attributable to other factors	(24.6)
Purchase price (initial fair value)	606.9
Allowance for credit losses	84.3
Amortized cost basis	691.2
Unpaid principal balance	7,107.9
Credit discount (1)	(76.5)
Non-credit discount	(9.2)
Fair value	7,022.2
Amortized cost basis	$ 7,713.4

Certain Loans Acquired in Transfer Accounted for as Available-for-Sale Debt Securities, Accrued Interest

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Loans Acquired in Transfer, Accretable Yield

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Loans Acquired In Transfer, Amortized cost basis

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Loans Acquired in Transfer, Contractually Required Payments Receivable at Acquisition

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Loans Acquired in Transfer, Nonaccretable Difference

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Loans Acquired in Transfer at Acquisition Fair Value

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value at acquisition of acquired loans accounted for as available-for-sale debt securities with evidence of deterioration of credit quality.

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Amount of expense to write-down the amortized cost basis of loans, after acquisition, to fair value when the decline in the fair value is determined to be other than temporary (OTTI) for loans accounted for as debt securities.

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The aggregate excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan. This relates to loans with deteriorating of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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The amount of the loan's contractually required payments receivable in excess of the amount of its cash flows expected to be collected. This relates to loans with deteriorating of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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Fair value at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Amount of cash flows expected to be collected at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Amount of contractually required payments receivable at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Reserve for loans impairments recorded after acquisition as a result of current information and events which result in it being probable that estimated cash flows will be less than previously expected or because actual cash flows are less than cash flows previously expected. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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