Loans (PCI Loans) (Details) $ in Millions	Dec. 31, 2019 USD ($)
Financing Receivable Impaired [Line Items]
Carrying Value	$ 1,598.3
Unpaid Principal Balance	2,325.3
Allowance for Loan Losses	113.6
Consumer Loans \| Legacy Consumer Mortgages
Financing Receivable Impaired [Line Items]
Allowance for Loan Losses	0.2
PCI Loans
Financing Receivable Impaired [Line Items]
Carrying Value	1,277.6
Unpaid Principal Balance	1,936.1
Allowance for Loan Losses	17.4
PCI Loans \| Commercial Loans \| Real Estate Finance
Financing Receivable Impaired [Line Items]
Carrying Value	27.8
Unpaid Principal Balance	30.4
Allowance for Loan Losses	9.8
PCI Loans \| Consumer Loans \| Legacy Consumer Mortgages
Financing Receivable Impaired [Line Items]
Carrying Value	1,249.8
Unpaid Principal Balance	1,905.7
Allowance for Loan Losses	$ 7.6

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Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953550-111524

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Amount of allowance for credit losses related to recorded investment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
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-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (a)(4)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

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