LOANS - Consumer Troubled Debt Restructurings (Details) - Consumer $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2016 USD ($) loan	Sep. 30, 2015 USD ($) loan	Sep. 30, 2016 USD ($) loan	Sep. 30, 2015 USD ($) loan	Dec. 31, 2015
Loans receivable
Period within which default occurred post-modification			1 year
Number of days past due, non-accrual status			60 days
Residential first mortgages
Loans receivable
Number of days past due, non-accrual status			90 days		90 days
Commercial banking
Loans receivable
Number of days past due, non-accrual status			90 days
In North America offices
Loans receivable
Number of loans modified \| loan	54,993	49,399	154,210	155,141
Post-modification recorded investment	$ 473	$ 546	$ 1,337	$ 1,852
Deferred principal	1	2	5	8
Contingent principal forgiveness	0	1	0	3
Principal forgiveness	1	7	3	26
TDR in payment default	$ 113	$ 160	$ 368	$ 509
In North America offices \| Residential first mortgages
Loans receivable
Number of loans modified \| loan	1,165	2,282	3,979	8,084
Post-modification recorded investment	$ 165	$ 305	$ 582	$ 1,078
Deferred principal	1	2	4	7
Contingent principal forgiveness	0	1	0	3
Principal forgiveness	$ 1	$ 7	$ 3	$ 23
Average interest rate reduction	1.00%	1.00%	1.00%	1.00%
Post-modification recorded investment for borrowers that have gone through Chapter 7 bankruptcy	$ 17	$ 54	$ 58	$ 181
TDR in payment default	49	101	188	329
In North America offices \| Residential first mortgages \| New OCC guidance
Loans receivable
Post-modification recorded investment for borrowers that have gone through Chapter 7 bankruptcy	$ 11	$ 34	$ 38	$ 107
In North America offices \| Home equity loans
Loans receivable
Number of loans modified \| loan	1,117	1,021	2,789	3,571
Post-modification recorded investment	$ 61	$ 36	$ 121	$ 126
Deferred principal	0	0	1	1
Contingent principal forgiveness	0	0	0	0
Principal forgiveness	$ 0	$ 0	$ 0	$ 3
Average interest rate reduction	2.00%	2.00%	2.00%	2.00%
Post-modification recorded investment for borrowers that have gone through Chapter 7 bankruptcy	$ 5	$ 17	$ 14	$ 46
TDR in payment default	6	9	20	30
In North America offices \| Home equity loans \| New OCC guidance
Loans receivable
Post-modification recorded investment for borrowers that have gone through Chapter 7 bankruptcy	$ 5	$ 14	$ 14	$ 39
In North America offices \| Credit cards
Loans receivable
Number of loans modified \| loan	51,260	44,972	143,161	140,130
Post-modification recorded investment	$ 199	$ 186	$ 552	$ 582
Deferred principal	0	0	0	0
Contingent principal forgiveness	0	0	0	0
Principal forgiveness	$ 0	$ 0	$ 0	$ 0
Average interest rate reduction	18.00%	16.00%	17.00%	16.00%
TDR in payment default	$ 43	$ 47	$ 139	$ 139
In North America offices \| Installment and other revolving
Loans receivable
Number of loans modified \| loan	1,421	1,035	4,187	3,111
Post-modification recorded investment	$ 12	$ 9	$ 35	$ 27
Deferred principal	0	0	0	0
Contingent principal forgiveness	0	0	0	0
Principal forgiveness	$ 0	$ 0	$ 0	$ 0
Average interest rate reduction	14.00%	13.00%	14.00%	13.00%
TDR in payment default	$ 3	$ 2	$ 7	$ 6
In North America offices \| Commercial banking
Loans receivable
Number of loans modified \| loan	30	89	94	245
Post-modification recorded investment	$ 36	$ 10	$ 47	$ 39
Deferred principal	0	0	0	0
Contingent principal forgiveness	0	0	0	0
Principal forgiveness	$ 0	$ 0	$ 0	$ 0
Average interest rate reduction	0.00%	0.00%	0.00%	0.00%
TDR in payment default	$ 12	$ 1	$ 14	$ 5
In offices outside the U.S.
Loans receivable
Number of loans modified \| loan	41,830	53,416	156,612	162,315
Post-modification recorded investment	$ 226	$ 204	$ 667	$ 636
Deferred principal	0	0	0	0
Contingent principal forgiveness	0	0	0	0
Principal forgiveness	4	3	13	10
TDR in payment default	$ 89	$ 66	$ 230	$ 205
In offices outside the U.S. \| Residential first mortgages
Loans receivable
Number of loans modified \| loan	973	1,322	2,005	2,963
Post-modification recorded investment	$ 24	$ 30	$ 62	$ 80
Deferred principal	0	0	0	0
Contingent principal forgiveness	0	0	0	0
Principal forgiveness	$ 0	$ 0	$ 0	$ 0
Average interest rate reduction	0.00%	0.00%	0.00%	0.00%
TDR in payment default	$ 3	$ 5	$ 9	$ 17
In offices outside the U.S. \| Credit cards
Loans receivable
Number of loans modified \| loan	28,530	32,774	109,365	110,792
Post-modification recorded investment	$ 94	$ 87	$ 307	$ 288
Deferred principal	0	0	0	0
Contingent principal forgiveness	0	0	0	0
Principal forgiveness	$ 2	$ 2	$ 7	$ 5
Average interest rate reduction	12.00%	13.00%	12.00%	13.00%
TDR in payment default	$ 41	$ 34	$ 115	$ 106
In offices outside the U.S. \| Installment and other revolving
Loans receivable
Number of loans modified \| loan	12,283	19,283	45,125	48,397
Post-modification recorded investment	$ 69	$ 76	$ 208	$ 207
Deferred principal	0	0	0	0
Contingent principal forgiveness	0	0	0	0
Principal forgiveness	$ 2	$ 1	$ 6	$ 5
Average interest rate reduction	8.00%	5.00%	7.00%	5.00%
TDR in payment default	$ 24	$ 20	$ 70	$ 66
In offices outside the U.S. \| Commercial banking
Loans receivable
Number of loans modified \| loan	44	37	117	163
Post-modification recorded investment	$ 39	$ 11	$ 90	$ 61
Deferred principal	0	0	0	0
Contingent principal forgiveness	0	0	0	0
Principal forgiveness	$ 0	$ 0	$ 0	$ 0
Average interest rate reduction	0.00%	0.00%	0.00%	1.00%
TDR in payment default	$ 21	$ 7	$ 36	$ 16

Represents the average interest rate reduction given under troubled debt restructurings.

No definition available.

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- Definition

This represents the period within which the payment default occurred after the loan modification.

+ References

No definition available.

+ Details

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- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified during the period by troubled debt restructurings after the financing receivable has been modified for borrowers that have gone through Chapter 7 bankruptcy.

+ References

No definition available.

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- Definition

Represents portion of loan principal that is non-interest bearing and, depending upon borrower performance, eligible for forgiveness.

+ References

No definition available.

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- Definition

The amount of principal was deferred during the period relating to the financing receivables modified by troubled debt restructurings. This portion of loan principal is non-interest bearing but still due from borrower.

+ References

No definition available.

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- Definition

The amount of principal was forgiven during the period relating to the financing receivables modified by troubled debt restructurings.

+ References

No definition available.

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- Definition

Represents the number of days, the loan is past due for classifying as non-accrual.

+ References

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

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953676-111524

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- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

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- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953682-111524

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