v3.26.3
Receivables and Revenue - Schedule of Partnership's Disaggregated Revenue (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 25, 2026
Sep. 26, 2025
Sep. 25, 2026
Sep. 26, 2025
Disaggregation Of Revenue [Line Items]        
Total revenue from customers $ 4,951 $ 4,299 $ 14,229 $ 12,203
Net interest and dividends and other revenue 182 240 583 738
Net revenue 5,133 4,539 14,812 12,941
U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 4,826 4,195 13,870 11,906
Net interest and dividends and other revenue 166 223 533 688
Net revenue 4,992 4,418 14,403 12,594
Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 125 104 359 297
Net interest and dividends and other revenue 16 17 50 50
Net revenue 141 121 409 347
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 4,335 3,667 12,328 10,307
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 4,229 3,580 12,027 10,065
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 106 87 301 242
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Advisory Programs Fees [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 3,509 2,886 9,905 8,036
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Advisory Programs Fees [Member] | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 3,431 2,826 9,686 7,873
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Advisory Programs Fees [Member] | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 78 60 219 163
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Service Fees [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 460 438 1,350 1,253
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Service Fees [Member] | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 432 411 1,268 1,174
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Service Fees [Member] | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 28 27 82 79
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Cash Solutions Fees Member        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 129 135 392 422
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Cash Solutions Fees Member | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 129 135 392 422
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Cash Solutions Fees Member | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 0 0 0 0
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Other Asset-based Fees [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 237 208 681 596
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Other Asset-based Fees [Member] | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 237 208 681 596
Location, Statement of Income, Balance [Axis]: us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax | Other Asset-based Fees [Member] | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 0 0 0 0
Location, Statement of Income, Balance [Axis]: us-gaap:Revenues        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 4,521 3,851 12,889 10,863
Location, Statement of Income, Balance [Axis]: us-gaap:Revenues | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 4,412 3,762 12,579 10,612
Location, Statement of Income, Balance [Axis]: us-gaap:Revenues | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 109 89 310 251
Location, Statement of Income, Balance [Axis]: us-gaap:RevenuesNetOfInterestExpense        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 430 448 1,340 1,340
Location, Statement of Income, Balance [Axis]: us-gaap:RevenuesNetOfInterestExpense | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 414 433 1,291 1,294
Location, Statement of Income, Balance [Axis]: us-gaap:RevenuesNetOfInterestExpense | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 16 15 49 46
Location, Statement of Income, Balance [Axis]: us-gaap:RevenuesNetOfInterestExpense | Commissions [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 376 382 1,175 1,149
Location, Statement of Income, Balance [Axis]: us-gaap:RevenuesNetOfInterestExpense | Commissions [Member] | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 363 370 1,133 1,111
Location, Statement of Income, Balance [Axis]: us-gaap:RevenuesNetOfInterestExpense | Commissions [Member] | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 13 12 42 38
Location, Statement of Income, Balance [Axis]: us-gaap:RevenuesNetOfInterestExpense | Principal Transactions [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 54 66 165 191
Location, Statement of Income, Balance [Axis]: us-gaap:RevenuesNetOfInterestExpense | Principal Transactions [Member] | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 51 63 158 183
Location, Statement of Income, Balance [Axis]: us-gaap:RevenuesNetOfInterestExpense | Principal Transactions [Member] | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 3 3 7 8
Location, Statement of Income, Balance [Axis]: ck0000815917:OtherRevenueLossNet        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 186 184 561 556
Location, Statement of Income, Balance [Axis]: ck0000815917:OtherRevenueLossNet | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 183 182 552 547
Location, Statement of Income, Balance [Axis]: ck0000815917:OtherRevenueLossNet | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 3 2 9 9
Location, Statement of Income, Balance [Axis]: ck0000815917:OtherRevenueLossNet | Shareholder Accounting Services Fees [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 114 115 342 348
Location, Statement of Income, Balance [Axis]: ck0000815917:OtherRevenueLossNet | Shareholder Accounting Services Fees [Member] | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 114 115 342 348
Location, Statement of Income, Balance [Axis]: ck0000815917:OtherRevenueLossNet | Shareholder Accounting Services Fees [Member] | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 0 0 0 0
Location, Statement of Income, Balance [Axis]: ck0000815917:OtherRevenueLossNet | Other Account and Activity Fee Revenue [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 72 69 219 208
Location, Statement of Income, Balance [Axis]: ck0000815917:OtherRevenueLossNet | Other Account and Activity Fee Revenue [Member] | U.S. [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers 69 67 210 199
Location, Statement of Income, Balance [Axis]: ck0000815917:OtherRevenueLossNet | Other Account and Activity Fee Revenue [Member] | Canada [Member]        
Disaggregation Of Revenue [Line Items]        
Total revenue from customers $ 3 $ 2 $ 9 $ 9