SUMMARY OF OPERATIONS AND SIGNIFICANT ACCOUNTING POLICIES (Details)	12 Months Ended
	Dec. 31, 2011 D M trust
Principles of Consolidation
Number of wholly owned subsidiaries that are statutory business trusts	7
Securities purchased under resale agreements ("Resale Agreements")
Resale agreement term, low end of range (in days)	1
Maximum term of resale agreement to be classified as cash and cash equivalents (in days)	90
Minimum term of resale agreement to be separately categorized (in days)	90
Investment securities
Maximum term of investment securities to be classified as trading account securities (in days)	7
Loans receivable
Number of past due days for the loans receivable to be placed on nonaccrual status (in days)	90
Troubled debt restructurings
Period for which restructured loans remains on nonaccrual status, to demonstrate that the borrower can perform under the restructured terms (in months)	6
Other real estate owned
Maximum period of foreclosure within which sale of real estate owned will be recorded at fair value less cost of sales (in months)	3
Investment in affordable housing partnerships
Minimum partnership interest required for equity method of accounting (as a percent)	5.00%
California
Operations summary
Number of banking locations (in branch)	103
New York
Operations summary
Number of banking locations (in branch)	8
Georgia
Operations summary
Number of banking locations (in branch)	5
Massachusetts
Operations summary
Number of banking locations (in branch)	3
Texas
Operations summary
Number of banking locations (in branch)	2
Washington
Operations summary
Number of banking locations (in branch)	4
In-store
Operations summary
Number of banking locations (in branch)	11
Greater China
Operations summary
Number of banking locations (in branch)	3