Contractual Maturity

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- Definition

Debt Instrument, Contractual Maturity, Term, Amortization Period

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No definition available.

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- Definition

Debt Instrument, Contractual Maturity, Term, Revolving Period

+ References

No definition available.

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- Definition

Debt Instrument, Unused Borrowing Capacity Fee, Percentage

+ References

No definition available.

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- Definition

Estimated weighted average life of student loans.

+ References

No definition available.

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- Definition

Lendable value of collateral

+ References

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Ownership Interest Percentage

+ References

No definition available.

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- Definition

Uncommitted Federal Funds

+ References

No definition available.

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- 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=82924980&loc=d3e107314-111719

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- Definition

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

+ References

No definition available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

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-Paragraph 2
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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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- 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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- 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

+ Details

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- 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=66007379&loc=d3e113888-111728

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-Name Accounting Standards Codification
-Topic 310
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- 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=82924980&loc=d3e107314-111719

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- 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
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3255-108585

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- 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 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(a))
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-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

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Borrowings - Additional (Details) - USD ($)								12 Months Ended
Borrowings - Additional (Details) - USD ($)	Feb. 21, 2018	Nov. 08, 2017	Feb. 22, 2017	Feb. 08, 2017	Oct. 12, 2016	Jul. 21, 2016	May 26, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Apr. 05, 2017	Oct. 27, 2015	Apr. 23, 2015
Debt Instrument [Line Items]
Amount drawn and outstanding under ABCP facility								$ 0	$ 0
Total Issued								1,448,000,000	1,782,000,000
Unsecured debt issued								$ 197,000,000	$ 0	$ 0
Estimated weighted average life of student loans								5 years 6 months	6 years
Discretionary uncommitted federal funds line of credit								$ 125,000,000
Lendable value of collateral								2,600,000,000
ABCP borrowings
Debt Instrument [Line Items]
Amount drawn and outstanding under ABCP facility								$ 0	$ 0
Contractual maturity related to ABCP facility								2 years
Revolving period of contractual maturity								1 year
Amortization period of contractual maturity								1 year
Private Education Loans
Debt Instrument [Line Items]
Private education loan term accounted for as a secured financing		$ 676,000,000		$ 772,000,000	$ 674,000,000	$ 657,000,000	$ 551,000,000
Ownership interest percentage on asset-backed financing		100.00%		100.00%
Loans sold to third parties												$ 701,000,000	$ 738,000,000
Unsecured debt issued		$ 674,000,000		$ 768,000,000
Class B Notes
Debt Instrument [Line Items]
Ownership interest percentage on asset-backed financing						100.00%	100.00%
Ownership interest amount of securitized or asset backed loan						$ 50,000,000	$ 50,000,000
Residual Certificates
Debt Instrument [Line Items]
Ownership interest percentage on asset-backed financing						100.00%	100.00%
Private Education Loans, Class A
Debt Instrument [Line Items]
Loans sold to third parties						$ 607,000,000	$ 501,000,000
Unsecured debt issued						$ 607,000,000	$ 501,000,000
Class A Notes
Debt Instrument [Line Items]
Estimated weighted average life of student loans						4 years 4 days	4 years 4 days
Private Education Loans, 2017 Term B
Debt Instrument [Line Items]
Loans pledged as collateral								$ 698,000,000
Private Education Loans, 2017 Term A
Debt Instrument [Line Items]
Loans pledged as collateral								733,000,000
Private Education Loans, 2016 Term A
Debt Instrument [Line Items]
Loans pledged as collateral								501,000,000
Private Education Loans, 2016 Term B
Debt Instrument [Line Items]
Loans pledged as collateral								$ 605,000,000
Class C Notes
Debt Instrument [Line Items]
Ownership interest percentage on asset-backed financing					100.00%
Loans sold to third parties					$ 674,000,000
Unsecured debt issued					$ 673,000,000
Class A and B Notes
Debt Instrument [Line Items]
Estimated weighted average life of student loans		4 years 26 days		4 years 3 months 8 days	4 years 3 months 7 days
Private Education Loans, 2016 Term C
Debt Instrument [Line Items]
Loans pledged as collateral					$ 612,000,000
London Interbank Offered Rate (LIBOR) \| Class A Notes
Debt Instrument [Line Items]
Basis spread on variable rate						1.36%	1.38%
London Interbank Offered Rate (LIBOR) \| Class A and B Notes
Debt Instrument [Line Items]
Basis spread on variable rate		0.80%		0.93%	1.15%
Commercial Paper \| ABCP borrowings
Debt Instrument [Line Items]
Private education loan funding			$ 750,000,000.0
Ownership Interest Percentage								100.00%
Commercial Paper \| London Interbank Offered Rate (LIBOR) \| ABCP borrowings
Debt Instrument [Line Items]
Basis spread on variable rate			0.85%
Minimum \| Commercial Paper \| ABCP borrowings
Debt Instrument [Line Items]
Unused borrowing capacity fee (as a percent)			0.35%
Maximum \| Commercial Paper \| ABCP borrowings
Debt Instrument [Line Items]
Unused borrowing capacity fee (as a percent)			0.45%
Unsecured Debt
Debt Instrument [Line Items]
Amount drawn and outstanding under ABCP facility								$ 0	$ 0
Unsecured Debt \| Senior Unsecured Notes Due April 5, 2022
Debt Instrument [Line Items]
Total Issued								$ 197,000,000			$ 200,000,000
Interest rate											5.125%
Subsequent Event \| Commercial Paper \| ABCP borrowings
Debt Instrument [Line Items]
Private education loan funding	$ 750,000,000.0
Subsequent Event \| Commercial Paper \| London Interbank Offered Rate (LIBOR) \| ABCP borrowings
Debt Instrument [Line Items]
Basis spread on variable rate	0.85%
Subsequent Event \| Minimum \| Commercial Paper \| ABCP borrowings
Debt Instrument [Line Items]
Unused borrowing capacity fee (as a percent)	0.35%
Subsequent Event \| Maximum \| Commercial Paper \| ABCP borrowings
Debt Instrument [Line Items]
Unused borrowing capacity fee (as a percent)	0.45%