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Goodwill and Acquired Intangible Assets - Carrying Value and Excess Percentage of Fair Value Over Carrying Value for Reporting Units (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013
FFELP Loans [Member]
Schedule Of Impaired Intangible Assets And Goodwill [Line Items]
Carrying Value of Equity	$ 930
% of Fair Value in Excess of Carrying Value	202.00%
Consumer Lending [Member]
Schedule Of Impaired Intangible Assets And Goodwill [Line Items]
Carrying Value of Equity	4,335
% of Fair Value in Excess of Carrying Value	80.00%
Servicing [Member]
Schedule Of Impaired Intangible Assets And Goodwill [Line Items]
Carrying Value of Equity	137
% of Fair Value in Excess of Carrying Value	966.00%
Contingency Services [Member]
Schedule Of Impaired Intangible Assets And Goodwill [Line Items]
Carrying Value of Equity	$ 53
% of Fair Value in Excess of Carrying Value	193.00%

X

- Definition

Represents the carrying value of equity for reporting units that had remaining goodwill at the end of the period.

+ References

No definition available.

+ Details

Name:	navi_CarryingValueOfEquityForReportingUnits
Namespace Prefix:	navi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	navi_ScheduleOfImpairedIntangibleAssetsAndGoodwillLineItems
Namespace Prefix:	navi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of fair value of reporting unit in excess of carrying amount.

+ References

No definition available.

+ Details

Name:	us-gaap_ReportingUnitPercentageOfFairValueInExcessOfCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant