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

Amount, before allowance for credit loss, fee, and loan in process, of financing receivable. Excludes financing receivable covered under loss sharing agreement.

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- Definition

Percentage of financing receivable balance that is past due.

+ References

No definition available.

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- Definition

Amount, before allowance for credit loss, of financing receivable.

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

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Allowance for Loan Losses - Age Analysis of Past Due Loans Delinquencies (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Loans in repayment and percentage of each status:
Loan allowance for losses	$ (1,219)	$ (1,274)	$ (1,271)	$ (1,377)
FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	51,268	57,155
Loan allowance for losses	(255)	(282)	(262)	$ (288)
Loans, net	51,013		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	7,093	7,818	7,256
Loan allowance for losses	(785)	(857)	(829)
Loans, net	$ 6,308	$ 6,961	$ 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	$ 13,959	$ 12,916	$ 13,924
Loan allowance for losses	(179)	(135)	(180)
Loans, net	$ 13,780	$ 12,781	$ 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	$ 51,268	$ 57,155	$ 52,903
Loan allowance for losses	(255)	(282)	(262)
Loans, net	$ 51,013	$ 56,873	$ 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	88.70%	94.00%	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	99.50%	99.70%	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	86.50%	91.70%	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	3.90%	2.30%	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	0.20%	0.10%	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	4.40%	3.00%	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	2.90%	1.30%	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	2.70%	1.80%	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	4.50%	2.40%	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	6.40%	3.50%	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	92.50%	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	98.10%	97.40%	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	83.30%	80.30%	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	11.30%	6.00%	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	0.50%	0.30%	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	13.50%	8.30%	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	4.90%	8.80%	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	0.60%	1.00%	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	12.90%	15.50%	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	$ 191	$ 255	$ 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	186	202	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	2,232	2,781	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	338	668	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	80	129	89
Forbearance [Member] \| Credit Concentration Risk [Member] \| Accounts Receivable [Member] \| FFELP Loans [Member]
Loans in repayment and percentage of each status:
Total Loans, gross	6,312	8,452	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	6,564	6,895	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	13,693	12,585	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	42,724	45,922	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	5,823	6,477	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	13,624	12,543	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	36,948	42,127	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	259	160	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	31	19	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	1,888	1,377	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	189	92	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	17	8	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	1,148	813	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	293	166	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	21	15	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	$ 2,740	$ 1,605	$ 2,112