ALLOWANCE FOR CREDIT LOSSES, NONPERFORMING ASSETS, AND CONCENTRATIONS OF CREDIT RISK - Summary of Changes in Allowance for Credit Losses (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2015	Jun. 30, 2014
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Beginning balance	$ 1,195
Provision charged to income	135	$ 170
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Ending balance	1,201
Allowance for loan and lease losses
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Beginning balance	1,195	1,221
Charge-offs	(236)	(245)
Recoveries	104	90
Net (charge-offs) recoveries	(132)	(155)
Sales/Other	(2)
Provision charged to income	140	144
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Ending balance	1,201	1,210
Allowance for loan and lease losses \| Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Beginning balance	544	498
Charge-offs	(21)	(14)
Recoveries	36	35
Net (charge-offs) recoveries	15	21
Sales/Other	0
Provision charged to income	6	(11)
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Ending balance	565	508
Allowance for loan and lease losses \| Retail
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Beginning balance	651	723
Charge-offs	(215)	(231)
Recoveries	68	55
Net (charge-offs) recoveries	(147)	(176)
Sales/Other	(2)
Provision charged to income	134	155
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Ending balance	636	702
Reserve for unfunded lending commitments
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Beginning balance	61	39
Credit for unfunded lending commitments	(5)	26
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Ending balance	56	65
Reserve for unfunded lending commitments \| Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Beginning balance	61	39
Credit for unfunded lending commitments	(5)	26
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Ending balance	56	65
Reserve for unfunded lending commitments \| Retail
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Beginning balance	0	0
Credit for unfunded lending commitments	0	0
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Ending balance	0	0
Allowance for loan and lease losses and reserve for off-balance sheet activities, total
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Ending balance	1,257	1,275
Allowance for loan and lease losses and reserve for off-balance sheet activities, total \| Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Ending balance	621	573
Allowance for loan and lease losses and reserve for off-balance sheet activities, total \| Retail
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for loan and lease losses / Reserve for unfunded lending commitments, Ending balance	$ 636	$ 702

Allowance related to loans transferred to held for sale.

No definition available.

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- Definition

Amount of credit for unfunded lending commitments recorded during the reporting period.

+ References

No definition available.

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- Definition

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

+ References

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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- Definition

Amount, after recoveries, of loans and leases that have been written-off.

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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

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- Definition

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

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