Loans and Allowance for Loan Losses (Details 2) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses, beginning of period	$ 879	$ 530	$ 721	$ 537
(Reversal of) provision for loan losses	34	(26)	(124)	(23)
Other			4	(1)
Loans charged-off	99	24	108	31
Recoveries of loans previously charged-off	1	4	6	8
Allowance for loan losses, end of period	747	536	747	536
Commercial portfolio
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses, beginning of period	822	459	651	465
(Reversal of) provision for loan losses	44	(12)	(127)	(7)
Other			4	(1)
Loans charged-off	97	(13)	(105)	(17)
Recoveries of loans previously charged-off	1	3	5	7
Allowance for loan losses, end of period	682	461	682	461
Consumer portfolio
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses, beginning of period	57	48	49	49
(Reversal of) provision for loan losses	(10)	(5)	(18)	(7)
Other			0	0
Loans charged-off	2	(3)	(3)	(6)
Recoveries of loans previously charged-off	0	1	1	1
Allowance for loan losses, end of period	65	51	65	51
Purchased credit-impaired loans
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses, beginning of period	0	3	1	3
(Reversal of) provision for loan losses	0	(9)	1	(9)
Other			0	0
Loans charged-off	0	(8)	0	(8)
Recoveries of loans previously charged-off	0	0	0	0
Allowance for loan losses, end of period	0	4	0	4
Unallocated portfolio
Financing Receivable, Allowance for Credit Losses
Allowance for loan losses, beginning of period	0	20	20	20
(Reversal of) provision for loan losses	0	0	20	0
Other			0	0
Loans charged-off	0	0	0	0
Recoveries of loans previously charged-off	0	0	0	0
Allowance for loan losses, end of period	$ 0	$ 20	$ 0	$ 20

Represents the amount of other allowance for credit losses related to financing receivable.

No definition available.

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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 recovery of financing receivables doubtful of collection that were previously charged off.

+ References

+ Details

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- Definition

Amount of direct write-downs of financing receivables charged against the allowance.

+ References

+ Details

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- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 6
-Section L
-Subsection 1

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- Definition

Amount of expense related to estimated loss from loan and lease transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

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-Publisher FASB
-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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-Section 50
-Paragraph 11B
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-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

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