Basis of presentation.

No definition available.

Name:	ck0000815917_BasisOfPresentationLineItems
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Assets or liabilities transferred into or out of levels I, II or III during the reporting period.

+ References

No definition available.

+ Details

Name:	ck0000815917_FairValueTransfersBetweenLevelsTransfersAmount
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of annual capital repayments to limited partners withdrawing from the partnership.

+ References

No definition available.

+ Details

Name:	ck0000815917_LimitedPartnersWithdrawalNumberOfAnnualCapitalRepayments
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The minimum annual return rate on the face amount of limited partnership capital.

+ References

No definition available.

+ Details

Name:	ck0000815917_LimitedPartnershipsMinimumAnnualPaymentRate
Namespace Prefix:	ck0000815917_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum period to receive distribution by limited partners.

+ References

No definition available.

+ Details

Name:	ck0000815917_MinimumPeriodToReceiveDistributionByLimitedPartners
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum period to receive distribution by subordinated limited partners.

+ References

No definition available.

+ Details

Name:	ck0000815917_MinimumPeriodToReceiveDistributionBySubordinatedLimitedPartners
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

New accounting pronouncement or change in accounting principle impact on consolidated statements of financial condition.

+ References

No definition available.

+ Details

Name:	ck0000815917_NewAccountingPronouncementOrChangeInAccountingPrincipleImpactOnConsolidatedStatementsOfFinancialCondition
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of classes of capital in the partnership.

+ References

No definition available.

+ Details

Name:	ck0000815917_NumberOfClassesOfCapital
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Partnership agreement partners capital redemption period.

+ References

No definition available.

+ Details

Name:	ck0000815917_PartnershipAgreementPartnersCapitalRedemptionPeriod
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Retirement transition employment agreement term.

+ References

No definition available.

+ Details

Name:	ck0000815917_RetirementTransitionEmploymentAgreementTerm
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Retirement transition plan accrued future payments.

+ References

No definition available.

+ Details

Name:	ck0000815917_RetirementTransitionPlanAccruedFuturePayments
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Retirement transition plan accrued future payments expected to be paid.

+ References

No definition available.

+ Details

Name:	ck0000815917_RetirementTransitionPlanAccruedFuturePaymentsExpectedToBePaid
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Term for compensation expense recognition under the retirement transition plan.

+ References

No definition available.

+ Details

Name:	ck0000815917_RetirementTransitionPlanCompensationExpenseTerm
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Retirement transition plan compensation on transitioned assets term.

+ References

No definition available.

+ Details

Name:	ck0000815917_RetirementTransitionPlanCompensationOnTransitionedAssetsTerm
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term for compensation paid under the retirement transition plan, which is made ratably over the period.

+ References

No definition available.

+ Details

Name:	ck0000815917_RetirementTransitionPlanCompensationPaidTerm
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term as employee under the retirement transition plan.

+ References

No definition available.

+ Details

Name:	ck0000815917_RetirementTransitionPlanEmploymentTerm
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term for non-compete agreement under the retirement transition plan.

+ References

No definition available.

+ Details

Name:	ck0000815917_RetirementTransitionPlanNonCompeteTerm
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Securities purchased under agreements to resell fair value of underlying collateral percentage.

+ References

No definition available.

+ Details

Name:	ck0000815917_SecuritiesPurchasedUnderAgreementsToResellFairValueOfUnderlyingCollateralPercentage
Namespace Prefix:	ck0000815917_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of annual capital repayments to subordinated limited partners withdrawing from the partnership.

+ References

No definition available.

+ Details

Name:	ck0000815917_SubordinatedLimitedPartnersWithdrawalNumberOfAnnualCapitalRepayments
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Assets categorized as level III during the reporting period.

+ References

No definition available.

+ Details

Name:	ck0000815917_UnobservableInputsAssetsFairValueDisclosure
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Liabilities categorized as level III during the reporting period.

+ References

No definition available.

+ Details

Name:	ck0000815917_UnobservableInputsLiabilitiesFairValueDisclosure
Namespace Prefix:	ck0000815917_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair value of collateral permitted, by contact or custom, to be sold or re-pledged.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

+ Details

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

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669619-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669625-108580

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(18))
-URI http://asc.fasb.org/extlink&oid=114873790&loc=SL114874131-224263

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

+ Details

Name:	us-gaap_NetIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cumulative effect of the change in accounting principle or new accounting pronouncement on retained earnings or other components of equity or net assets in the statement of financial position as of the beginning of the earliest period presented.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22499-107794

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22580-107794

+ Details

Name:	us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleCumulativeEffectOfChangeOnEquityOrNetAssets1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfOperatingSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

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

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

Name:	us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash and cash equivalents restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(2))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=98513485&loc=SL98516268-108586

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(1)(a))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3044-108585

+ Details

Name:	us-gaap_RestrictedCashAndCashEquivalents
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

+ Details

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201409Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis=us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201602Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201618Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_CA
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_EquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=ck0000815917_SecuritiesPurchaseAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018 USD ($) Segment Capital_Repayment CapitalClass	Dec. 31, 2017 USD ($) Segment	Dec. 31, 2016 USD ($) Segment	Jan. 01, 2018 USD ($)	Dec. 31, 2015 USD ($)
Basis Of Presentation [Line Items]
Number of operating segments \| Segment	2	2	2
Period for partner's capital redemption in the event of death	6 months
Number of annual capital repayments for withdrawal of limited partners \| Segment	3
Period to begin repaying capital upon withdrawal for limited partners	90 days
Number of annual capital repayments for withdrawal of subordinated limited partners \| Capital_Repayment	6
Period to begin repaying capital upon withdrawal for subordinated limited partners	90 days
Fair value of level III, assets	$ 0	$ 0
Fair value of level III, liabilities	0	0
Transfers between levels I, II and III	0	0
Fair value of collateral related to resell agreements	$ 926,000,000	1,184,000,000
Retirement and transition employment agreement term	5 years
Retirement transition plan employment term	2 years
Retirement transition plan non-compete term	3 years
Retirement transition plan compensation paid term	4 years
Retirement transition plan accrued future payments	$ 94,000,000	78,000,000
Retirement transition plan accrued future payments expected to be paid in 2019	45,000,000
Net income	$ 0	$ 0	$ 0
Number of classes of capital \| CapitalClass	3
Limited partnership's minimum annual return rate	7.50%	7.50%	7.50%
Revenue	$ 8,215,000,000	$ 7,272,000,000	$ 6,405,000,000
ASU 2014-09 [Member]
Basis Of Presentation [Line Items]
Impact to partnership capital				$ 0
ASU 2014-09 [Member] \| Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Basis Of Presentation [Line Items]
Revenue	0
Impact to consolidated statements of financial condition	0
ASU 2016-02 [Member]
Basis Of Presentation [Line Items]
Impact to partnership capital	0
Expected lease asset	805,000,000
Expected lease liability	805,000,000
ASU 2016-18 [Member]
Basis Of Presentation [Line Items]
Restricted cash	$ 7,239,000,000	$ 7,691,000,000	8,525,000,000		$ 6,970,000,000
Building [Member]
Basis Of Presentation [Line Items]
Equipment, property and improvements estimated useful lives	30 years
United States [Member]
Basis Of Presentation [Line Items]
Fair value of underlying collateral as percentage of carrying value of transaction	102.00%	102.00%
Revenue	$ 8,002,000,000	$ 7,084,000,000	6,238,000,000
Canada [Member]
Basis Of Presentation [Line Items]
Fair value of underlying collateral as percentage of carrying value of transaction	100.00%	100.00%
Revenue	$ 213,000,000	$ 188,000,000	$ 167,000,000
Minimum [Member]
Basis Of Presentation [Line Items]
Retirement transition plan compensation expense term	1 year
Minimum [Member] \| Equipment [Member]
Basis Of Presentation [Line Items]
Equipment, property and improvements estimated useful lives	3 years
Maximum [Member]
Basis Of Presentation [Line Items]
Retirement transition plan compensation expense term	2 years
Retirement transition plan compensation on transitioned assets term	4 years
Maximum [Member] \| Equipment [Member]
Basis Of Presentation [Line Items]
Equipment, property and improvements estimated useful lives	7 years
Securities Purchase Agreement [Member] \| Minimum [Member] \| United States [Member]
Basis Of Presentation [Line Items]
Fair value of underlying collateral as percentage of carrying value of transaction	102.00%
Securities Purchase Agreement [Member] \| Minimum [Member] \| Canada [Member]
Basis Of Presentation [Line Items]
Fair value of underlying collateral as percentage of carrying value of transaction	100.00%