Receivables and Revenue - Schedule of Partnership's Disaggregated Revenue (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 24, 2021	Sep. 30, 2022	Sep. 24, 2021
Disaggregation Of Revenue [Line Items]
Net revenue	$ 2,968	$ 3,109	$ 9,040	$ 8,923
Net interest and dividends and other revenue	82	31	57	104
Net revenue	3,050	3,140	9,097	9,027
United States [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	2,888	3,030	8,794	8,696
Net interest and dividends and other revenue	67	22	26	89
Net revenue	2,955	3,052	8,820	8,785
Canada [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	80	79	246	227
Net interest and dividends and other revenue	15	9	31	15
Net revenue	95	88	277	242
Total Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	2,613	2,707	7,904	7,642
Total Fee Revenue [Member] | United States [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	2,546	2,640	7,699	7,456
Total Fee Revenue [Member] | Canada [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	67	67	205	186
Asset-based Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	2,438	2,535	7,385	7,129
Asset-based Fee Revenue [Member] | Advisory Programs Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	1,821	1,938	5,589	5,418
Asset-based Fee Revenue [Member] | Service Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	366	432	1,156	1,240
Asset-based Fee Revenue [Member] | Other Asset-based Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	251	165	640	471
Asset-based Fee Revenue [Member] | United States [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	2,375	2,472	7,191	6,954
Asset-based Fee Revenue [Member] | United States [Member] | Advisory Programs Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	1,784	1,904	5,478	5,326
Asset-based Fee Revenue [Member] | United States [Member] | Service Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	340	403	1,073	1,157
Asset-based Fee Revenue [Member] | United States [Member] | Other Asset-based Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	251	165	640	471
Asset-based Fee Revenue [Member] | Canada [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	63	63	194	175
Asset-based Fee Revenue [Member] | Canada [Member] | Advisory Programs Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	37	34	111	92
Asset-based Fee Revenue [Member] | Canada [Member] | Service Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	26	29	83	83
Asset-based Fee Revenue [Member] | Canada [Member] | Other Asset-based Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	0	0	0	0
Account and Activity Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	175	172	519	513
Account and Activity Fee Revenue [Member] | Shareholder Accounting Services Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	116	109	340	325
Account and Activity Fee Revenue [Member] | Other Account and Activity Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	59	63	179	188
Account and Activity Fee Revenue [Member] | United States [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	171	168	508	502
Account and Activity Fee Revenue [Member] | United States [Member] | Shareholder Accounting Services Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	116	109	340	325
Account and Activity Fee Revenue [Member] | United States [Member] | Other Account and Activity Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	55	59	168	177
Account and Activity Fee Revenue [Member] | Canada [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	4	4	11	11
Account and Activity Fee Revenue [Member] | Canada [Member] | Shareholder Accounting Services Fees [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	0	0	0	0
Account and Activity Fee Revenue [Member] | Canada [Member] | Other Account and Activity Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	4	4	11	11
Trade Revenue [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	355	402	1,136	1,281
Trade Revenue [Member] | Commissions [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	301	392	1,031	1,251
Trade Revenue [Member] | Principal Transactions [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	54	10	105	30
Trade Revenue [Member] | United States [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	342	390	1,095	1,240
Trade Revenue [Member] | United States [Member] | Commissions [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	291	381	995	1,212
Trade Revenue [Member] | United States [Member] | Principal Transactions [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	51	9	100	28
Trade Revenue [Member] | Canada [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	13	12	41	41
Trade Revenue [Member] | Canada [Member] | Commissions [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	10	11	36	39
Trade Revenue [Member] | Canada [Member] | Principal Transactions [Member]
Disaggregation Of Revenue [Line Items]
Net revenue	$ 3	$ 1	$ 5	$ 2