Loans In Repayment And Percentage Of Each Status [Abstract]

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

+ References

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- Definition

Amortized cost, before allowance for credit loss, fee, and loan in process, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

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- Definition

Percentage of financing receivable balance that is past due.

+ References

No definition available.

+ Details

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- Definition

Amortized cost, before allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

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- Definition

Amortized cost, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

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Allowance for Loan Losses - Age Analysis of Past Due Loans Delinquencies (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Loans in repayment and percentage of each status:
Loan allowance for losses	$ (832)	$ (1,022)	$ (1,271)	$ (1,377)
Loans, net	54,827	62,250
Private Education Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	17,519	19,525	21,180
Loan allowance for losses	(617)	(800)	(1,009)	(1,089)
Loans, net	16,902	18,725
FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	38,140	43,747	52,903
Loan allowance for losses	(215)	(222)	$ (262)	$ (288)
Loans, net	37,925	43,525
Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	17,519	19,525
Loan allowance for losses	(617)	(800)
Loans, net	16,902	18,725
Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	38,140	43,747
Loan allowance for losses	(215)	(222)
Loans, net	$ 37,925	$ 43,525
Dimensions of concentration risk	100.00%	100.00%
Credit Concentration Risk [Member] \| Financing Receivables, Current [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	94.90%	95.00%
Credit Concentration Risk [Member] \| Financing Receivables, Current [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	86.10%	84.40%
Credit Concentration Risk [Member] \| Financing Receivables, 31 to 60 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	1.80%	1.80%
Credit Concentration Risk [Member] \| Financing Receivables, 31 to 60 Days Past Due [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	3.90%	3.60%
Credit Concentration Risk [Member] \| Financing Receivables, 61 to 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	1.00%	1.00%
Credit Concentration Risk [Member] \| Financing Receivables, 61 to 90 Days Past Due [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	2.50%	2.40%
Credit Concentration Risk [Member] \| Financing Receivables, 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	2.30%	2.20%
Credit Concentration Risk [Member] \| Financing Receivables, 90 Days Past Due [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	7.50%	9.60%
Credit Concentration Risk [Member] \| Financing Receivables, Loans In Repayment [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	95.90%	96.10%
Credit Concentration Risk [Member] \| Financing Receivables, Loans In Repayment [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	79.80%	78.60%
Credit Concentration Risk [Member] \| Financing Receivables, Delinquent Loans in Repayment [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	5.10%	5.00%
Credit Concentration Risk [Member] \| Financing Receivables, Delinquent Loans in Repayment [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	13.90%	15.60%
Credit Concentration Risk [Member] \| Financing Receivables, Forbearance, Loans In Repayment [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	2.10%	2.10%
Credit Concentration Risk [Member] \| Financing Receivables, Forbearance, Loans In Repayment [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	16.80%	18.10%
School/Grace/Deferment [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	$ 360	$ 354
School/Grace/Deferment [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	1,557	1,772
Forbearance [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	363	401
Forbearance [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	6,147	7,603
Repayment [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	$ 16,796	$ 18,770
Dimensions of concentration risk	100.00%	100.00%
Repayment [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	$ 30,436	$ 34,372
Repayment [Member] \| Credit Concentration Risk [Member] \| Financing Asset, Not Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	15,935	17,838
Repayment [Member] \| Credit Concentration Risk [Member] \| Financing Asset, Not Past Due [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	26,204	29,004
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 31 to 60 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	308	335
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 31 to 60 Days Past Due [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	1,193	1,247
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 61 to 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	173	186
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 61 to 90 Days Past Due [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	746	833
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	380	411
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 90 Days Past Due [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	$ 2,293	$ 3,288