LOANS AND LEASES - Summary of Loans and Leases Portfolio (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	$ 41,470,000,000		$ 39,395,000,000
Total retail	49,279,000,000		46,464,000,000
Total loans and leases	90,749,000,000	[1],[2]	85,859,000,000	[1],[2]
Loans held for sale	205,000,000		176,000,000
Residential Mortgage and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	208,000,000		1,300,000,000
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	30,356,000,000		28,667,000,000
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	7,239,000,000		6,948,000,000
Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	3,875,000,000		3,780,000,000
Residential, including originated home equity products
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retail	30,458,000,000		29,694,000,000
Home equity products serviced by others
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retail	1,870,000,000		2,171,000,000
Other secured retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retail	13,206,000,000		10,700,000,000
Unsecured retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retail	3,745,000,000		3,899,000,000
Banking Subsidiaries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans serviced for others by the Company's subsidiaries	$ 18,100,000,000		$ 18,700,000,000

[1] Excluded from the table above are loans held for sale totaling $208 million as of September 30, 2014 and $1.3 billion as of December 31, 2013. The December 31, 2013 loans held for sale balance primarily related to the Company's sale of certain assets and liabilities associated with its Chicago-area retail branches. For further discussion, see Note 13 "Divestitures and Branch Assets and Liabilities Held for Sale" to the Company's unaudited interim Consolidated Financial Statements included in Part I, Item 1 — Financial Information.

[2] Mortgage loans serviced for others by the Company's subsidiaries are not included above, and amounted to $18.1 billion and $18.7 billion at September 30, 2014 and December 31, 2013, respectively.