BASIS OF PRESENTATION AND ACCOUNTING POLICIES (Details) (USD $)	3 Months Ended		6 Months Ended					6 Months Ended																6 Months Ended						12 Months Ended	0 Months Ended	6 Months Ended	12 Months Ended	0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014		Jun. 30, 2013		Dec. 31, 2013	Jun. 30, 2014 Automobiles [Member]	Jun. 30, 2014 Minimum [Member] Office buildings [Member]	Jun. 30, 2014 Minimum [Member] Leasehold improvements [Member]		Jun. 30, 2014 Minimum [Member] Software [Member]		Jun. 30, 2014 Minimum [Member] Furniture, fixtures and equipment [Member]	Jun. 30, 2014 Maximum [Member] Office buildings [Member]	Jun. 30, 2014 Maximum [Member] Leasehold improvements [Member]		Jun. 30, 2014 Maximum [Member] Software [Member]		Jun. 30, 2014 Maximum [Member] Furniture, fixtures and equipment [Member]	Jun. 30, 2014 Commercial loans and consumer loans [Member]	Jun. 30, 2014 Credit card receivable [Member]	Jun. 30, 2014 Commercial loan [Member] Minimum [Member]	Jun. 30, 2014 Consumer loan [Member]	Jun. 30, 2014 Consumer loans not secured by real estate [Member]	Jun. 30, 2014 Auto loans [Member]	Jun. 30, 2014 Retail installment contracts [Member]	Jun. 30, 2014 Unsecured revolving loan [Member]	Jun. 30, 2014 Term loan [Member]	Dec. 31, 2013 Other Assets [Member]	Jan. 28, 2014 SCUSA [Member]	Jun. 30, 2014 SCUSA [Member]	Dec. 31, 2013 SCUSA [Member]	Jan. 28, 2014 SCUSA [Member] IPO [Member]	Aug. 06, 2014 Subsequent Event [Member]
Basis of Presentation and Accounting Policies [Line Items]
Ownership percentage before sale of stock																																	65.00%
Number of shares issued																															13,895,243			85,242,042
Ownership percentage after sale of stock																															61.00%
Amount reclassified to Core Deposit Intangibles and Other Intangibles																														$ 34,600,000
Loans transferred from held for investment to held for sale			225,262,000	[1]	14,898,000	[1]																													695,000,000
FHLB Stock, par value (in usd per share)	$ 100		$ 100
Minimum days of loan payment delinquent that interest income not recognized																					90 days	180 days
Threshold period after receipt of notification of death or bankruptcy																						60 days
Impaired loans, minimum commercial non-accrual loans	2,969,496,000		2,969,496,000				1,430,588,000																1,000,000
Period of time not resulting loan identified as impaired			90 days
Threshold period past due for charged-off of loans																								180 days	120 days	121 days	120 days	180 days	120 days
Premises and equipment, useful lives								5 years	10 years	10 years	[2]	3 years	[3]	3 years	30 years	30 years	[2]	5 years	[3]	10 years
Impairment of long-lived assets	97,546,000	0	97,546,000		0
Goodwill recognized			5,476,844,000																													5,485,196,000
Intangible assets recognized																																478,800,000
OREO and other repossessed assets	$ 228,200,000		$ 228,200,000				$ 91,700,000

[1] The Change in Control and subsequent consolidation of SCUSA was accounted for as a non-cash transaction. See Note 3 to the Condensed Consolidated Financial Statements for detail on the Change in Control.

[2] Leasehold improvements are depreciated over the shorter of the useful lives of the assets or the remaining term of the leases. The useful life of the leasehold improvements may be extended beyond the base term of the lease contract when the lease contract includes renewal option period(s) that are reasonably assured of being exercised at the date the leasehold improvements are purchased. At no point does the depreciable life exceed the economic useful life of the leasehold improvement or the expected term of the lease contract.

[3] Standard depreciable period for software is three years. However, for larger software implementation projects, a five-year period is utilized. For the 2012 information technology ("IT") transformation, the Company utilized a depreciable period of five years.