ALLOWANCE FOR CREDIT LOSSES, NONPERFORMING ASSETS, AND CONCENTRATIONS OF CREDIT RISK - Default of Modified Debt Agreements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014 contract	Sep. 30, 2013 contract	Sep. 30, 2014 contract	Sep. 30, 2013 contract
Financing Receivable, Modifications [Line Items]
Number of Contracts	532	845	1,596	2,843
Balance Defaulted	$ 29	$ 27	$ 73	$ 125
Commercial
Financing Receivable, Modifications [Line Items]
Number of Contracts	5	7	22	8
Balance Defaulted	4	1	7	1
Commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts	1	0	2	1
Balance Defaulted	0	0	1	0
Total commercial
Financing Receivable, Modifications [Line Items]
Number of Contracts	6	7	24	9
Balance Defaulted	4	1	8	1
Residential, including originated home equity products
Financing Receivable, Modifications [Line Items]
Number of Contracts	247	289	676	1,413
Balance Defaulted	22	19	55	104
Home equity products serviced by others
Financing Receivable, Modifications [Line Items]
Number of Contracts	23	51	69	201
Balance Defaulted	0	0	1	4
Other secured retail
Financing Receivable, Modifications [Line Items]
Number of Contracts	32	84	99	214
Balance Defaulted	0	1	1	2
Unsecured retail
Financing Receivable, Modifications [Line Items]
Number of Contracts	224	414	728	1,006
Balance Defaulted	3	6	8	14
Total retail
Financing Receivable, Modifications [Line Items]
Number of Contracts	526	838	1,572	2,834
Balance Defaulted	$ 25	$ 26	$ 65	$ 124