ALLOWANCE FOR CREDIT LOSSES, NONPERFORMING ASSETS, AND CONCENTRATIONS OF CREDIT RISK - Recorded Investment in Retail Loans by Delinquency Status (Details) - Loans and Leases - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total		$ 96,538	$ 93,410
Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		11,853	11,352
1-29 Days Past Due		89	114
30-89 Days Past Due		65	97
90 Days or More Past Due		246	269
Total		12,253	11,832
Home equity loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		2,652	2,997
1-29 Days Past Due		187	222
30-89 Days Past Due		48	60
90 Days or More Past Due		135	145
Total		3,022	3,424
Home equity lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		14,253	14,705
1-29 Days Past Due		406	447
30-89 Days Past Due		73	73
90 Days or More Past Due		185	198
Total		14,917	15,423
Home equity loans serviced by others
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	1,027	1,101
1-29 Days Past Due	[1]	58	78
30-89 Days Past Due	[1]	20	26
90 Days or More Past Due	[1]	21	23
Total	[1]	1,126	1,228
Home equity lines of credit serviced by others
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	390	455
1-29 Days Past Due	[1]	61	66
30-89 Days Past Due	[1]	22	10
90 Days or More Past Due	[1]	21	19
Total	[1]	494	550
Automobile
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		12,817	11,839
1-29 Days Past Due		784	758
30-89 Days Past Due		104	93
90 Days or More Past Due		22	16
Total		13,727	12,706
Student
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		3,209	2,106
1-29 Days Past Due		87	108
30-89 Days Past Due		24	25
90 Days or More Past Due		35	17
Total		3,355	2,256
Credit cards
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		1,542	1,615
1-29 Days Past Due		39	39
30-89 Days Past Due		18	22
90 Days or More Past Due		14	17
Total		1,613	1,693
Other retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		889	985
1-29 Days Past Due		57	65
30-89 Days Past Due		14	18
90 Days or More Past Due		3	4
Total		963	1,072
Total retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		48,632	47,155
1-29 Days Past Due		1,768	1,897
30-89 Days Past Due		388	424
90 Days or More Past Due		682	708
Total		$ 51,470	$ 50,184

[1] The Company’s SBO portfolio consists of purchased home equity loans and lines that were originally serviced by others. The Company now services a portion of this portfolio internally.