ALLOWANCE FOR CREDIT LOSSES, NONPERFORMING ASSETS, AND CONCENTRATIONS OF CREDIT RISK - Impaired Loans by Class (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Larger balance commercial loans minimum balance	$ 3
Impaired Loans With a Related Allowance	779	832
Allowance on Impaired Loans	130	131
Impaired Loans Without a Related Allowance	638	607
Unpaid Contractual Balance	1,755	1,885
Total Recorded Investment in Impaired Loans	1,417	1,439
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Impaired Loans With a Related Allowance	116	86
Allowance on Impaired Loans	14	15
Impaired Loans Without a Related Allowance	53	33
Unpaid Contractual Balance	195	214
Total Recorded Investment in Impaired Loans	169	119
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Impaired Loans With a Related Allowance	0	76
Allowance on Impaired Loans	0	8
Impaired Loans Without a Related Allowance	34	44
Unpaid Contractual Balance	72	221
Total Recorded Investment in Impaired Loans	34	120
Total commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Impaired Loans With a Related Allowance	116	162
Allowance on Impaired Loans	14	23
Impaired Loans Without a Related Allowance	87	77
Unpaid Contractual Balance	267	435
Total Recorded Investment in Impaired Loans	203	239
Residential, including originated home equity products
Financing Receivable, Recorded Investment, Past Due [Line Items]
Impaired Loans With a Related Allowance	361	355
Allowance on Impaired Loans	57	59
Impaired Loans Without a Related Allowance	518	497
Unpaid Contractual Balance	1,131	1,081
Total Recorded Investment in Impaired Loans	879	852
Home equity products serviced by others
Financing Receivable, Recorded Investment, Past Due [Line Items]
Impaired Loans With a Related Allowance	83	91
Allowance on Impaired Loans	14	11
Impaired Loans Without a Related Allowance	23	21
Unpaid Contractual Balance	120	125
Total Recorded Investment in Impaired Loans	106	112
Other secured retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Impaired Loans With a Related Allowance	21	23
Allowance on Impaired Loans	4	3
Impaired Loans Without a Related Allowance	10	12
Unpaid Contractual Balance	39	43
Total Recorded Investment in Impaired Loans	31	35
Unsecured retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Impaired Loans With a Related Allowance	198	201
Allowance on Impaired Loans	41	35
Impaired Loans Without a Related Allowance	0	0
Unpaid Contractual Balance	198	201
Total Recorded Investment in Impaired Loans	198	201
Total retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Impaired Loans With a Related Allowance	663	670
Allowance on Impaired Loans	116	108
Impaired Loans Without a Related Allowance	551	530
Unpaid Contractual Balance	1,488	1,450
Total Recorded Investment in Impaired Loans	$ 1,214	$ 1,200