ALLOWANCE FOR CREDIT LOSSES, NONPERFORMING ASSETS, AND CONCENTRATIONS OF CREDIT RISK - Additional Impaired Loan Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Interest Income Recognized	$ 13	$ 10	$ 35	$ 24
Average Recorded Investment	1,396	1,421	1,368	1,407
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Interest Income Recognized	2	1	2	2
Average Recorded Investment	138	154	141	169
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Interest Income Recognized	0	0	1	1
Average Recorded Investment	62	154	70	172
Total commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Interest Income Recognized	2	1	3	3
Average Recorded Investment	200	308	211	341
Residential, including originated home equity products
Financing Receivable, Recorded Investment, Past Due [Line Items]
Interest Income Recognized	6	6	19	9
Average Recorded Investment	865	762	835	727
Home equity products serviced by others
Financing Receivable, Recorded Investment, Past Due [Line Items]
Interest Income Recognized	1	1	4	4
Average Recorded Investment	106	118	105	119
Other secured retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Interest Income Recognized	1	(4)	1	0
Average Recorded Investment	30	36	29	35
Unsecured retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Interest Income Recognized	3	6	8	8
Average Recorded Investment	195	197	188	185
Total retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Interest Income Recognized	11	9	32	21
Average Recorded Investment	$ 1,196	$ 1,113	$ 1,157	$ 1,066