Receivables and Revenue - Schedule of Partnership's Disaggregated Revenue (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 29, 2023	Sep. 30, 2022	Sep. 29, 2023	Sep. 30, 2022
Disaggregation Of Revenue [Line Items]
Total revenue from customers	$ 3,253	$ 2,968	$ 9,415	$ 9,040
Net interest and dividends and other revenue	240	82	737	57
Net revenue	3,493	3,050	10,152	9,097
United States [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	3,170	2,888	9,175	8,794
Net interest and dividends and other revenue	224	67	688	26
Net revenue	3,394	2,955	9,863	8,820
Canada [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	83	80	240	246
Net interest and dividends and other revenue	16	15	49	31
Net revenue	99	95	289	277
Total Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	2,894	2,613	8,371	7,904
Total Fee Revenue [Member] | United States [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	2,824	2,546	8,169	7,699
Total Fee Revenue [Member] | Canada [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	70	67	202	205
Asset-based Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	2,708	2,438	7,809	7,385
Asset-based Fee Revenue [Member] | Advisory Programs Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	2,015	1,821	5,789	5,589
Asset-based Fee Revenue [Member] | Service Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	378	366	1,107	1,156
Asset-based Fee Revenue [Member] | Other Asset-based Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	165	157	485	480
Asset-based Fee Revenue [Member] | Cash Solutions Fees Member
Disaggregation Of Revenue [Line Items]
Total revenue from customers	150	94	428	160
Asset-based Fee Revenue [Member] | United States [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	2,641	2,375	7,617	7,191
Asset-based Fee Revenue [Member] | United States [Member] | Advisory Programs Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	1,974	1,784	5,672	5,478
Asset-based Fee Revenue [Member] | United States [Member] | Service Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	352	340	1,032	1,073
Asset-based Fee Revenue [Member] | United States [Member] | Other Asset-based Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	165	157	485	480
Asset-based Fee Revenue [Member] | United States [Member] | Cash Solutions Fees Member
Disaggregation Of Revenue [Line Items]
Total revenue from customers	150	94	428	160
Asset-based Fee Revenue [Member] | Canada [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	67	63	192	194
Asset-based Fee Revenue [Member] | Canada [Member] | Advisory Programs Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	41	37	117	111
Asset-based Fee Revenue [Member] | Canada [Member] | Service Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	26	26	75	83
Asset-based Fee Revenue [Member] | Canada [Member] | Other Asset-based Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	0	0	0	0
Asset-based Fee Revenue [Member] | Canada [Member] | Cash Solutions Fees Member
Disaggregation Of Revenue [Line Items]
Total revenue from customers	0	0	0	0
Account and Activity Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	186	175	562	519
Account and Activity Fee Revenue [Member] | Shareholder Accounting Services Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	116	116	346	340
Account and Activity Fee Revenue [Member] | Other Account and Activity Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	70	59	216	179
Account and Activity Fee Revenue [Member] | United States [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	183	171	552	508
Account and Activity Fee Revenue [Member] | United States [Member] | Shareholder Accounting Services Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	116	116	346	340
Account and Activity Fee Revenue [Member] | United States [Member] | Other Account and Activity Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	67	55	206	168
Account and Activity Fee Revenue [Member] | Canada [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	3	4	10	11
Account and Activity Fee Revenue [Member] | Canada [Member] | Shareholder Accounting Services Fees [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	0	0	0	0
Account and Activity Fee Revenue [Member] | Canada [Member] | Other Account and Activity Fee Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	3	4	10	11
Trade Revenue [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	359	355	1,044	1,136
Trade Revenue [Member] | Commissions [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	304	301	886	1,031
Trade Revenue [Member] | Principal Transactions [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	55	54	158	105
Trade Revenue [Member] | United States [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	346	342	1,006	1,095
Trade Revenue [Member] | United States [Member] | Commissions [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	294	291	855	995
Trade Revenue [Member] | United States [Member] | Principal Transactions [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	52	51	151	100
Trade Revenue [Member] | Canada [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	13	13	38	41
Trade Revenue [Member] | Canada [Member] | Commissions [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	10	10	31	36
Trade Revenue [Member] | Canada [Member] | Principal Transactions [Member]
Disaggregation Of Revenue [Line Items]
Total revenue from customers	$ 3	$ 3	$ 7	$ 5