Loans and Leases - Impaired Loans (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
CRE - property development - acquired credit impaired
Financing Receivable, Impaired [Line Items]
Recorded investment with no related allowance	$ 0	$ 0
Unpaid principal balance with no related allowance recorded	34	34
CRE - other - acquired credit impaired
Financing Receivable, Impaired [Line Items]
Recorded investment with no related allowance	0	0
Unpaid principal balance with no related allowance recorded	22	22
Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Recorded investment with no related allowance	0	0
Unpaid principal balance with no related allowance recorded	56	56
Institutional
Financing Receivable, Impaired [Line Items]
Amount of loan losses related to institutional loans collectively evaluated for impairment	$ 46	$ 38

The balance of financing receivables that were collectively evaluated for impairment.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

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- Definition

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.

+ References

No definition available.

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- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953550-111524

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- Definition

Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (a)(4)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5212-111524

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