Subsequent Event - Additional Information (Details) - Subsequent Event [Member] $ in Millions	Nov. 04, 2026 USD ($)
2026 Credit Facility [Member]
Subsequent Event [Line Items]
Line of credit facility	$ 750
Maximum leverage ratio required to be maintained by partnership	35.00%
Required minimum partnership capital, net of reserve for anticipated withdrawals and partnership loans	$ 3,811
Minimum tangible net worth	$ 1,592
Minimum regulatory net capital percentage of debit items	6.00%
2022 Credit Facility [Member]
Subsequent Event [Line Items]
Line of credit facility	$ 500

Maximum leverage ratio required to be maintained by partnership.

No definition available.

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- Definition

Minimum regulatory net capital percentage of debit items.

+ References

No definition available.

+ Details

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- Definition

Minimum tangible net worth required to be maintained.

+ References

No definition available.

+ Details

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Namespace Prefix:	ck0000815917_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Required minimum partnership capital net of reserve for anticipated withdrawals and partnership loans.

+ References

No definition available.

+ Details

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Namespace Prefix:	ck0000815917_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480657/210-10-S50-8

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

+ Details

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Balance Type:	na
Period Type:	duration

- Details

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- Details

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- Details

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