Lines of Credit - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
Sep. 28, 2018	Dec. 31, 2021	Dec. 31, 2020
Line Of Credit Facility [Line Items]
Line of credit facility		$ 890,000,000	$ 890,000,000
2018 Credit Facility [Member]
Line Of Credit Facility [Line Items]
Line of credit facility	$ 500,000,000	$ 500,000,000	$ 500,000,000
Maximum leverage ratio required to be maintained by partnership	35.00%	35.00%	35.00%
Required minimum partnership capital, net of reserve for anticipated withdrawals and partnership loans	$ 1,884,000,000	$ 1,884,000,000	$ 1,884,000,000
Minimum tangible net worth	$ 1,344,000,000	$ 1,344,000,000	$ 1,344,000,000
Minimum regulatory net capital percentage of debit items	6.00%	6.00%	6.00%
Amount outstanding under credit facility		$ 0	$ 0
Partnership draws against lines of credit		0	0
Uncommitted Secured Credit Facilities [Member]
Line Of Credit Facility [Line Items]
Line of credit facility		390,000,000	390,000,000
Amount outstanding under credit facility		0	0
Partnership draws against lines of credit		$ 0	$ 0

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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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Partnership draws against lines of credit.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: 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(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: 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(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 3: 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(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

+ Details

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Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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- 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

+ Details

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- Details

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- Details

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