Borrowings - Short Term Borrowings (Details) - USD ($)		12 Months Ended
Jul. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Short-term Debt [Line Items]
Short-Term		$ 0	$ 0
Weighted Average Interest Rate		0.00%
Average Balance		$ 122,396,000
Weighted Average Interest Rate(1)		5.78%
Maximum outstanding at any month end		$ 199,651,000	289,230,000
Borrowing limit increase		2,000,000,000	2,000,000,000
Senior Unsecured Notes Due April 5, 2022
Short-term Debt [Line Items]
Short-Term		$ 0
Weighted Average Interest Rate		0.00%
Average Balance		$ 122,396,000
Weighted Average Interest Rate(1)		5.78%
Secured Borrowing Facility
Short-term Debt [Line Items]
Short-Term		$ 0	$ 0
Contractual maturity related to ABCP facility		2 years
Weighted Average Interest Rate		0.00%	0.00%
Average Balance		$ 0	$ 45,820,000
Weighted Average Interest Rate(1)		0.00%	24.99%
Commercial Paper \| Secured Borrowing Facility
Short-term Debt [Line Items]
Private education loan funding	$ 2,000,000,000
Ownership interest percentage	100.00%
Short-Term		$ 0	$ 0

Contractual Maturity

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Ownership Interest Percentage

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- Definition

The average effective interest rate during the reporting period.

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Amount of increase (decrease) of the credit facility.

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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.

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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.

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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.

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Weighted average interest rate of short-term debt outstanding calculated at point in time.

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period.

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, maximum month-end borrowings during the period.

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