Debt Instrument, Unused Borrowing Capacity Fee, Percentage

No definition available.

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- Definition

Estimated weighted average life of student loans.

+ References

No definition available.

+ Details

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- Definition

Lendable value of collateral

+ References

No definition available.

+ Details

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

- Definition

Line of Credit Facility, Percent Outstanding of Borrowing Capacity

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Line of Credit, Required Ownership Interest

+ References

No definition available.

+ Details

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

- Definition

Loans Securitized or Asset-backed Financing Arrangement, Ownership Interest, Amount

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Loans Securitized or Asset-backed Financing Arrangement, Ownership Interest, Percentage

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Uncommitted Federal Funds

+ References

No definition available.

+ Details

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

- Definition

Principal amount of transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction. Continuing involvement includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=51814546&loc=d3e107314-111719

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

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Balance Type:	na
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- 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

+ Details

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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

- Definition

Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6467456&loc=d3e113888-111728

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5086-111524

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

This is the principal amount outstanding for loans which are in the process of being securitized as of the date of the statement of financial position (across all types of loans).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=51814546&loc=d3e107314-111719

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow from the issuance of long-term debt that is not secured by collateral. Excludes proceeds from tax exempt unsecured debt.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ 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 210.9-03.13)

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

Reference 2: 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(a))

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

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.(a),16(a)(1))

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

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13

-Subparagraph 2, 3

-Article 9

+ Details

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Balance Type:	credit
Period Type:	instant

- Details

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- Details

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- Details

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- Details

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- Details

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Borrowings - Additional Information (Details) - USD ($)			9 Months Ended	12 Months Ended
Borrowings - Additional Information (Details) - USD ($)	Jul. 30, 2015	Dec. 19, 2014	Sep. 30, 2015	Dec. 31, 2014	Apr. 23, 2015
Line of Credit Facility [Line Items]
Estimated weighted average life of student loans			6 years 3 months 8 days	6 years 2 months 8 days
Short-term borrowings			$ 710,005,000	$ 0
Uncommitted federal funds			100,000
Lendable value of collateral			1,500,000,000	$ 1,400,000,000
Private Education Loans
Line of Credit Facility [Line Items]
Outstanding amount of asset-backed loan	$ 714,000,000
Sale of Private Education Loans	631,000,000				$ 738,000,000
Gross proceeds on securitization	$ 623,000,000
Loans pledged as collateral			692,000,000
Class A and B Notes
Line of Credit Facility [Line Items]
Ownership interest as a percentage	5.00%
Estimated weighted average life of student loans	4 years 9 months 18 days
Ownership interest amount	$ 33,000,000
Class C Notes
Line of Credit Facility [Line Items]
Ownership interest as a percentage	100.00%
Ownership interest amount	$ 50,000,000
Residual Certificates
Line of Credit Facility [Line Items]
Ownership interest as a percentage	100.00%
ABCP borrowings
Line of Credit Facility [Line Items]
Short-term borrowings			710,005,000
Loans pledged as collateral			$ 902,000,000
ABCP borrowings \| Commercial Paper
Line of Credit Facility [Line Items]
Private asset backed commercial paper education loan funding facility		$ 750,000,000
Ownership interest percentage in loan facility		5.00%
Required ownership interest		$ 37,500,000
Funds available for Private Education Loan originations		$ 712,500,000.0
Financing cost percentage of unused borrowing capacity		0.40%
LIBOR \| Class A and B Notes
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.53%
LIBOR \| ABCP borrowings \| Commercial Paper
Line of Credit Facility [Line Items]
Basis spread on variable rate		0.80%