Represents amount committed under commitments.

No definition available.

Name:	sov_CommitmentsAmountCommitted
Namespace Prefix:	sov_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	sov_CommitmentsLineItems
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Balance Type:	na
Period Type:	duration

- Definition

Weighted average term of commitment

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Derivative, Maturity Period

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount committed expiring in next twelve months under commitments.

+ References

No definition available.

+ Details

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Namespace Prefix:	sov_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability, Over Five Years

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents amount committed expiring in the next two to three years under commitments.

+ References

No definition available.

+ Details

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Namespace Prefix:	sov_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability, Over Three Years to Five Years

+ References

No definition available.

+ Details

Name:	sov_FairValueDisclosureOffBalanceSheetRisksFaceAmountLiabilityOverThreeYearsToFiveYears
Namespace Prefix:	sov_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Loan Purchase Commitment, Amount

+ References

No definition available.

+ Details

Name:	sov_LoanPurchaseCommitmentAmount
Namespace Prefix:	sov_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Loan Purchase Commitment, Cancellation Period

+ References

No definition available.

+ Details

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Namespace Prefix:	sov_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Loan Purchase Commitment, Percentage of Lending Entity's Near-Prime Originations

+ References

No definition available.

+ Details

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Namespace Prefix:	sov_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Loans Sold with Recourse, Maximum Exposure

+ References

No definition available.

+ Details

Name:	sov_LoansSoldwithRecourseMaximumExposure
Namespace Prefix:	sov_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Portion (in percent) of first credit loss position on loans sold with recourse retained.

+ References

No definition available.

+ Details

Name:	sov_LoansSoldWithRecoursePortionOfFirstCreditLossPositionRetainedPercent
Namespace Prefix:	sov_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Loans Sold with Recourse, Repurchase Amount

+ References

No definition available.

+ Details

Name:	sov_LoansSoldwithRecourseRepurchaseAmount
Namespace Prefix:	sov_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Unpaid principal balance of loans sold with recourse at period end.

+ References

No definition available.

+ Details

Name:	sov_LoansSoldWithRecourseUnpaidPrincipalBalance
Namespace Prefix:	sov_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Profit (Loss) Sharing Payment, Percentage

+ References

No definition available.

+ Details

Name:	sov_ProfitLossSharingPaymentPercentage
Namespace Prefix:	sov_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Reserve for unfunded loan commitments and letters of credit.

+ References

No definition available.

+ Details

Name:	sov_ReserveForUnfundedCommitments
Namespace Prefix:	sov_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Retained Credit Risk, Multifamily Servicing

+ References

No definition available.

+ Details

Name:	sov_RetainedCreditRiskMultifamilyServicing
Namespace Prefix:	sov_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	sov_SCUSACommitmentsAbstract
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Balance Type:	na
Period Type:	duration

- Definition

The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4H

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624258-113959

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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- Details

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- Details

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COMMITMENTS, CONTINGENCIES, AND GUARANTEES (Off-Balance Sheet Risk and Guarantees) (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Commitments [Line Items]
Total commitments	32,138,312,000sov_CommitmentsAmountCommitted		$ 26,771,985,000sov_CommitmentsAmountCommitted
Reserve for unfunded lending commitments	149,641,000sov_ReserveForUnfundedCommitments	170,274,000sov_ReserveForUnfundedCommitments	220,000,000sov_ReserveForUnfundedCommitments	210,000,000sov_ReserveForUnfundedCommitments	210,000,000sov_ReserveForUnfundedCommitments	210,000,000sov_ReserveForUnfundedCommitments
Line of credit outstanding	78,200,000us-gaap_LineOfCredit		90,200,000us-gaap_LineOfCredit
Retained credit risk, multifamily servicing	47,100,000		68,000,000
Collateral posted	121,700,000		203,900,000
SCUSA [Member] \| Maximum [Member] \| CBP [Member]
SCUSA Commitments [Abstract]
Loss-sharing payment percentage	0.50%
Residential mortgages [Member]
Commitments [Line Items]
Loans sold with recourse, maximum exposure	23,400,000		25,600,000
FNMA [Member]
Commitments [Line Items]
Repurchase amount of loans	1,500,000,000
FNMA [Member] \| Multi-family loans [Member]
Commitments [Line Items]
Loans sold with recourse, portion of first credit loss position retained, percent	100.00%
Repurchase amount of loans	816,500,000
Commitments to extend credit [Member]
Commitments [Line Items]
One year or less	5,289,599,000		5,163,591,000
Over 1 year to 3 years	5,917,705,000		5,716,759,000
Over 3 years to 5 years	9,911,406,000		6,457,992,000
Over 5 years	6,438,702,000		6,313,449,000
Total commitments	27,557,412,000		23,651,791,000
Unsecured revolving lines of credit [Member]
Commitments [Line Items]
Total commitments	2,298,694,000		815,573,000
Letters of credit [Member]
Commitments [Line Items]
One year or less	1,450,905,000		1,680,277,000
Over 1 year to 3 years	295,290,000		333,769,000
Over 3 years to 5 years	256,928,000		96,558,000
Over 5 years	6,893,000		5,623,000
Total commitments	2,010,016,000		2,116,227,000
Commitments, weighted average term	13 years 9 months
Value of underlying collateral	447,900,000
Reserve for unfunded lending commitments	71,400,000		129,800,000
Letters of credit [Member] \| SCUSA [Member] \| Letters of credit [Member]
SCUSA Commitments [Abstract]
Letter of credit, maximum borrowing capacity	500,000,000
Letters of credit outstanding	0
Recourse and credit enhancement exposure on sold loans [Member]
Commitments [Line Items]
Total commitments	176,247,000		184,584,000
Collateral posted	900,000		900,000
Recourse and credit enhancement exposure on sold loans [Member] \| Residential mortgages [Member]
Commitments [Line Items]
Loans sold with recourse, unpaid principal balance	58,800,000		65,700,000
Recourse and credit enhancement exposure on sold loans [Member] \| FNMA [Member] \| Multi-family loans [Member]
Commitments [Line Items]
Value of underlying collateral	152,800,000		159,000,000
Loans sold with recourse, unpaid principal balance	2,900,000,000		4,300,000,000
Commitments to sell loans [Member]
Commitments [Line Items]
Total commitments	95,943,000		3,810,000
Forward contracts maturity period (less than one year)	1 year
Commitments to sell loans [Member] \| SCUSA [Member] \| Maximum [Member]
Commitments [Line Items]
Total commitments	300,000,000
Commitments to sell loans [Member] \| SCUSA [Member] \| Obligation to Repurchase Receivables Sold [Member]
Commitments [Line Items]
Total commitments	17,100,000
Loan purchase commitments [Member] \| SCUSA [Member]
SCUSA Commitments [Abstract]
Loan purchase commitment, cancellation pPeriod	90 days
Loan purchase commitments [Member] \| SCUSA [Member] \| Minimum [Member] \| July 2014 to July 2015 [Member]
SCUSA Commitments [Abstract]
Loan purchase commitment amount	30,000,000
Loan purchase commitment, as a percentage of lending entity's near-prime originations	75.00%
Loan purchase commitments [Member] \| SCUSA [Member] \| Minimum [Member] \| July 2014 to July 2017 [Member]
SCUSA Commitments [Abstract]
Loan purchase commitment amount	30,000,000
Loan purchase commitment, as a percentage of lending entity's near-prime originations	50.00%