Fair Value - Partnership's Financial Assets at Fair Value (Detail) - USD ($) $ in Millions	Jun. 24, 2022	Dec. 31, 2021
Cash equivalents:
Total cash equivalents	$ 411	$ 313
Investments segregated under federal regulations:
Total investments segregated under federal regulations	14,920	14,308
Investment securities:
Total investment securities	743	852
Inventory securities:
Total inventory securities	42	38
Other Assets [Abstract]
Client Fractional Shares Ownership Assets	630	710
Accounts Payable and Accrued Liabilities [Abstract]
Client Fractional Shares Redemption Obligations	630	710
Equities [Member]
Investment securities:
Total investment securities	12	3
Inventory securities:
Total inventory securities	8	18
Corporate Bonds and Notes [Member]
Inventory securities:
Total inventory securities	5	3
Government and Agency Obligations [Member]
Investment securities:
Total investment securities	412	413
U.S. Treasuries [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	14,520	13,908
Mutual Funds [Member]
Investment securities:
Total investment securities	319	366
Inventory securities:
Total inventory securities	10	2
State and Municipal Obligations [Member]
Inventory securities:
Total inventory securities	18	9
Certificates of Deposit [Member]
Cash equivalents:
Total cash equivalents	384	266
Investments segregated under federal regulations:
Total investments segregated under federal regulations	400	400
Investment securities:
Total investment securities		70
Inventory securities:
Total inventory securities	1	6
Money Market Fund [Member]
Cash equivalents:
Total cash equivalents	27	47
Level I [Member]
Cash equivalents:
Total cash equivalents	27	47
Investments segregated under federal regulations:
Total investments segregated under federal regulations	14,520	13,908
Investment securities:
Total investment securities	743	782
Inventory securities:
Total inventory securities	18	20
Other Assets [Abstract]
Client Fractional Shares Ownership Assets	630	710
Accounts Payable and Accrued Liabilities [Abstract]
Client Fractional Shares Redemption Obligations	630	710
Level I [Member] | Equities [Member]
Investment securities:
Total investment securities	12	3
Inventory securities:
Total inventory securities	8	18
Level I [Member] | Corporate Bonds and Notes [Member]
Inventory securities:
Total inventory securities	0	0
Level I [Member] | Government and Agency Obligations [Member]
Investment securities:
Total investment securities	412	413
Level I [Member] | U.S. Treasuries [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	14,520	13,908
Level I [Member] | Mutual Funds [Member]
Investment securities:
Total investment securities	319	366
Inventory securities:
Total inventory securities	10	2
Level I [Member] | State and Municipal Obligations [Member]
Inventory securities:
Total inventory securities	0	0
Level I [Member] | Certificates of Deposit [Member]
Cash equivalents:
Total cash equivalents	0	0
Investments segregated under federal regulations:
Total investments segregated under federal regulations	0	0
Investment securities:
Total investment securities		0
Inventory securities:
Total inventory securities	0	0
Level I [Member] | Money Market Fund [Member]
Cash equivalents:
Total cash equivalents	27	47
Level II [Member]
Cash equivalents:
Total cash equivalents	384	266
Investments segregated under federal regulations:
Total investments segregated under federal regulations	400	400
Investment securities:
Total investment securities	0	70
Inventory securities:
Total inventory securities	24	18
Other Assets [Abstract]
Client Fractional Shares Ownership Assets	0	0
Accounts Payable and Accrued Liabilities [Abstract]
Client Fractional Shares Redemption Obligations	0	0
Level II [Member] | Equities [Member]
Investment securities:
Total investment securities	0	0
Inventory securities:
Total inventory securities	0	0
Level II [Member] | Corporate Bonds and Notes [Member]
Inventory securities:
Total inventory securities	5	3
Level II [Member] | Government and Agency Obligations [Member]
Investment securities:
Total investment securities	0	0
Level II [Member] | U.S. Treasuries [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	0	0
Level II [Member] | Mutual Funds [Member]
Investment securities:
Total investment securities	0	0
Inventory securities:
Total inventory securities	0	0
Level II [Member] | State and Municipal Obligations [Member]
Inventory securities:
Total inventory securities	18	9
Level II [Member] | Certificates of Deposit [Member]
Cash equivalents:
Total cash equivalents	384	266
Investments segregated under federal regulations:
Total investments segregated under federal regulations	400	400
Investment securities:
Total investment securities		70
Inventory securities:
Total inventory securities	1	6
Level II [Member] | Money Market Fund [Member]
Cash equivalents:
Total cash equivalents	$ 0	$ 0