v3.26.3
Segment Information - Financial Information for Partnership's Reportable Segments (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 25, 2026
Sep. 26, 2025
Sep. 25, 2026
Sep. 26, 2025
Dec. 31, 2025
Revenues From External Customers And Long Lived Assets [Line Items]          
Net revenue $ 5,133 $ 4,539 $ 14,812 $ 12,941  
FA compensation and benefits 1,991 1,758 5,867 5,103  
Home office operating expense 1,013 849 2,852 2,532  
Branch office operating expense 664 616 1,954 1,807  
Variable compensation 835 790 2,363 1,989  
Operating expenses 4,503 4,013 13,036 11,431  
Income before allocations $ 630 $ 526 $ 1,776 $ 1,510  
Income before allocations margin 12.20% 11.50% 11.90% 11.50%  
Net interest and dividends revenue $ 185 $ 211 $ 558 $ 646  
Depreciation and amortization 215 190 617 533  
Total assets 27,940 27,726 27,940 27,726 $ 30,508
U.S. [Member]          
Revenues From External Customers And Long Lived Assets [Line Items]          
Net revenue 4,992 4,418 14,403 12,594  
FA compensation and benefits 1,935 1,710 5,702 4,961  
Home office operating expense 982 822 2,759 2,451  
Branch office operating expense 645 597 1,896 1,753  
Variable compensation 816 774 2,311 1,946  
Operating expenses 4,378 3,903 12,668 11,111  
Income before allocations $ 614 $ 515 $ 1,735 $ 1,483  
Income before allocations margin 12.20% 11.50% 11.90% 11.60%  
Net interest and dividends revenue $ 177 $ 201 $ 531 $ 614  
Depreciation and amortization 210 183 606 517  
Total assets 26,461 26,461 26,461 26,461  
Canada [Member]          
Revenues From External Customers And Long Lived Assets [Line Items]          
Net revenue 141 121 409 347  
FA compensation and benefits 56 48 165 142  
Home office operating expense 31 27 93 81  
Branch office operating expense 19 19 58 54  
Variable compensation 19 16 52 43  
Operating expenses 125 110 368 320  
Income before allocations $ 16 $ 11 $ 41 $ 27  
Income before allocations margin 11.30% 9.30% 10.00% 7.80%  
Net interest and dividends revenue $ 8 $ 10 $ 27 $ 32  
Depreciation and amortization 5 7 11 16  
Total assets $ 1,479 $ 1,265 $ 1,479 $ 1,265