LOANS - Corporate Loans Credit Quality Indicators (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Loans receivable
Loans, net of unearned income	$ 628,595	$ 624,369
Loans at fair value	4,035	3,486
Corporate
Loans receivable
Loans, net of unearned income	308,039	299,306
Total non-accrual	2,339	2,421
Loans at fair value	4,007	3,457
Corporate \| Commercial and industrial
Loans receivable
Loans, net of unearned income	134,445	129,116
Total non-accrual	1,692	1,909
Corporate \| Financial institutions
Loans receivable
Loans, net of unearned income	68,012	61,560
Total non-accrual	301	185
Corporate \| Mortgage and real estate
Loans receivable
Loans, net of unearned income	45,564	44,031
Total non-accrual	181	139
Corporate \| Lease financing
Loans receivable
Loans, net of unearned income	1,764	1,769
Total non-accrual	67	56
Corporate \| Other
Loans receivable
Loans, net of unearned income	54,247	59,373
Total non-accrual	98	132
Corporate \| Private bank loans managed on a delinquency basis
Loans receivable
Loans, net of unearned income	23,618	23,353
Corporate \| Investment grade
Loans receivable
Loans, net of unearned income	214,552	207,235
Corporate \| Investment grade \| Commercial and industrial
Loans receivable
Loans, net of unearned income	90,753	85,369
Corporate \| Investment grade \| Financial institutions
Loans receivable
Loans, net of unearned income	55,422	49,915
Corporate \| Investment grade \| Mortgage and real estate
Loans receivable
Loans, net of unearned income	19,901	18,718
Corporate \| Investment grade \| Lease financing
Loans receivable
Loans, net of unearned income	1,169	1,303
Corporate \| Investment grade \| Other
Loans receivable
Loans, net of unearned income	47,307	51,930
Corporate \| Non-investment grade
Loans receivable
Loans, net of unearned income	65,862	65,261
Corporate \| Non-investment grade \| Commercial and industrial
Loans receivable
Loans, net of unearned income	41,999	41,838
Total non-accrual	1,692	1,909
Corporate \| Non-investment grade \| Financial institutions
Loans receivable
Loans, net of unearned income	12,288	11,459
Total non-accrual	301	185
Corporate \| Non-investment grade \| Mortgage and real estate
Loans receivable
Loans, net of unearned income	1,865	1,821
Total non-accrual	181	139
Corporate \| Non-investment grade \| Lease financing
Loans receivable
Loans, net of unearned income	528	410
Total non-accrual	67	56
Corporate \| Non-investment grade \| Other
Loans receivable
Loans, net of unearned income	6,843	7,312
Total non-accrual	$ 98	$ 132

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- Definition

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Recorded Investment
-URI http://asc.fasb.org/extlink&oid=65880944

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5111-111524

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes 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 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
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-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5074-111524

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=6517073

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