Loans (Loans On Non-accrual Status) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	$ 220.9	$ 278.6
Repossessed assets and OREO	54.6	72.7
Total non-performing assets	275.5	351.3
Commercial loans past due 90 days or more accruing	11.7	7.2
Consumer loans past due 90 days or more accruing	20.2	24.8
Total Accruing loans past due 90 days or more	31.9	32.0
Held for Investment
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	211.1	236.2
Held for Sale
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	9.8	42.4
Commercial Banking
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	190.8	250.9
Commercial Banking \| Held for Investment
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	190.8	218.8
Commercial Banking \| Held for Sale
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	0.0	32.1
Commercial Banking \| Commercial Finance
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	134.8	188.8
Commercial Banking \| Commercial Finance \| Held for Investment
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	134.8	156.7
Commercial Banking \| Real Estate Finance
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	2.8	20.4
Commercial Banking \| Real Estate Finance \| Held for Investment
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	2.8	20.4
Commercial Banking \| Business Capital
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	53.2	41.7
Commercial Banking \| Business Capital \| Held for Investment
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	53.2	41.7
Consumer Banking
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	20.3	17.4
Consumer Banking \| Held for Investment
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	20.3	17.4
Consumer Banking \| Held for Sale
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total		0.0
Consumer Banking \| LCM
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	19.9	17.3
Consumer Banking \| LCM \| Held for Investment
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	19.9	17.3
Consumer Banking \| LCM \| Held for Sale
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total		0.0
Consumer Banking \| Other Consumer Banking
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	0.4	0.1
Consumer Banking \| Other Consumer Banking \| Held for Investment
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	0.4	0.1
Consumer Banking \| Other Consumer Banking \| Held for Sale
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total		0.0
Non-Strategic Portfolios
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	9.8	10.3
Non-Strategic Portfolios \| Held for Sale
Finance Receivables Non Accrual Status By Type Of Holding [Line Items]
Total	$ 9.8	$ 10.3

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-Publisher FASB
-Name Accounting Standards Codification
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