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.

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- Definition

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

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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.

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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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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	9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2020
Loans in repayment and percentage of each status:
Loan allowance for losses	$ (1,085)	$ (1,249)	$ (1,271)	$ (1,166)	$ (1,253)	$ (1,377)
FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	47,124	54,619
Loan allowance for losses	(233)	(269)	(262)	$ (245)	$ (277)	$ (288)
Loans, net	46,891		52,641
Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	6,796	7,411	7,256
Loan allowance for losses	(666)	(814)	(829)
Loans, net	$ 6,130	$ 6,597	$ 6,427
Dimensions of concentration risk	100.00%	100.00%	100.00%
Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	$ 13,207	$ 13,587	$ 13,924
Loan allowance for losses	(186)	(166)	(180)
Loans, net	$ 13,021	$ 13,421	$ 13,744
Dimensions of concentration risk	100.00%	100.00%	100.00%
Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	$ 47,124	$ 54,619	$ 52,903
Loan allowance for losses	(233)	(269)	(262)
Loans, net	$ 46,891	$ 54,350	$ 52,641
Dimensions of concentration risk	100.00%	100.00%	100.00%
Credit Concentration Risk [Member] \| Financing Receivables, Current [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	87.80%	91.60%	91.00%
Credit Concentration Risk [Member] \| Financing Receivables, Current [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	99.40%	99.60%	99.60%
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	81.40%	91.50%	89.40%
Credit Concentration Risk [Member] \| Financing Receivables, 31 to 60 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	4.20%	3.50%	3.00%
Credit Concentration Risk [Member] \| Financing Receivables, 31 to 60 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	0.30%	0.20%	0.20%
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	5.10%	2.70%	3.80%
Credit Concentration Risk [Member] \| Financing Receivables, 61 to 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	2.30%	1.90%	1.80%
Credit Concentration Risk [Member] \| Financing Receivables, 61 to 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	0.10%	0.10%	0.10%
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	3.40%	1.50%	2.00%
Credit Concentration Risk [Member] \| Financing Receivables, 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	5.70%	3.00%	4.20%
Credit Concentration Risk [Member] \| Financing Receivables, 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Loans delinquent, percentage	0.20%	0.10%	0.10%
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	10.10%	4.30%	4.80%
Credit Concentration Risk [Member] \| Financing Receivables, Loans In Repayment [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	93.40%	88.20%	91.20%
Credit Concentration Risk [Member] \| Financing Receivables, Loans In Repayment [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	97.90%	97.60%	98.20%
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	80.10%	80.90%	83.90%
Credit Concentration Risk [Member] \| Financing Receivables, Delinquent Loans in Repayment [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	12.20%	8.40%	9.00%
Credit Concentration Risk [Member] \| Financing Receivables, Delinquent Loans in Repayment [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	0.60%	0.40%	0.40%
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	18.60%	8.50%	10.60%
Credit Concentration Risk [Member] \| Financing Receivables, Forbearance, Loans In Repayment [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	4.30%	9.30%	6.30%
Credit Concentration Risk [Member] \| Financing Receivables, Forbearance, Loans In Repayment [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Dimensions of concentration risk	0.70%	1.10%	0.60%
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	16.40%	15.40%	12.40%
School/Grace/Deferment [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	$ 164	$ 210	$ 194
School/Grace/Deferment [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	184	179	167
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	1,983	2,430	2,220
Forbearance [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	284	667	446
Forbearance [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	87	147	89
Forbearance [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	7,410	8,029	6,292
Repayment [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	6,348	6,534	6,616
Repayment [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	12,936	13,261	13,668
Repayment [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	37,731	44,160	44,391
Repayment [Member] \| Credit Concentration Risk [Member] \| Financing Asset, Not Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	5,573	5,988	6,023
Repayment [Member] \| Credit Concentration Risk [Member] \| Financing Asset, Not Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	12,853	13,208	13,611
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	30,720	40,404	39,679
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 31 to 60 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	269	224	199
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 31 to 60 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	36	23	23
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	1,917	1,181	1,696
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 61 to 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	143	124	120
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 61 to 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	16	12	11
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	1,291	665	904
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	363	198	274
Repayment [Member] \| Credit Concentration Risk [Member] \| Financial Asset, 90 Days Past Due [Member] \| Accounts Receivable [Member] \| Private Education Loans - Non-TDRs [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	31	18	23
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	$ 3,803	$ 1,910	$ 2,112