ALLOWANCE FOR CREDIT LOSSES, NONPERFORMING ASSETS, AND CONCENTRATIONS OF CREDIT RISK - Accruing and Nonaccruing Past Due Amounts (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	$ 471	$ 554
90 Days or More Past Due	842	1,057
Total Past Due	1,313	1,611
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	30	61
90 Days or More Past Due	93	96
Total Past Due	123	157
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	42	34
90 Days or More Past Due	83	169
Total Past Due	125	203
Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	2	24
90 Days or More Past Due	0	0
Total Past Due	2	24
Total commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	74	119
90 Days or More Past Due	176	265
Total Past Due	250	384
Residential, including originated home equity products
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	227	259
90 Days or More Past Due	568	662
Total Past Due	795	921
Home equity products serviced by others
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	42	43
90 Days or More Past Due	52	60
Total Past Due	94	103
Other secured retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	79	66
90 Days or More Past Due	16	16
Total Past Due	95	82
Unsecured retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	49	67
90 Days or More Past Due	30	54
Total Past Due	79	121
Total retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	397	435
90 Days or More Past Due	666	792
Total Past Due	$ 1,063	$ 1,227