Fair Value - Partnership's Financial Assets at Fair Value (Detail) (USD $) In Millions, unless otherwise specified	Mar. 28, 2014	Dec. 31, 2013
Investments segregated under federal regulations:
Total investments segregated under federal regulations	$ 1,377	$ 1,379
Inventory securities:
Total inventory securities	96	102
Investment securities:
Total investment securities	138	141
State and municipal obligations [Member]
Inventory securities:
Total inventory securities	54	67
Unit investment trusts [Member]
Inventory securities:
Total inventory securities		2
Other [Member]
Inventory securities:
Total inventory securities	2	1
Investment securities:
Total investment securities	1	1
Mutual funds [Member]
Investment securities:
Total investment securities	113	116
Government and agency obligations [Member]
Investment securities:
Total investment securities	19	19
U.S. treasuries [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	1,152	1,154
Equities [Member]
Inventory securities:
Total inventory securities	37	27
Investment securities:
Total investment securities	5	5
Corporate bonds and notes [Member]
Inventory securities:
Total inventory securities	3	3
Certificates of deposit [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	225	225
Inventory securities:
Total inventory securities		2
Level I [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	1,152	1,154
Inventory securities:
Total inventory securities	38	29
Investment securities:
Total investment securities	137	140
Level I [Member] | State and municipal obligations [Member]
Inventory securities:
Total inventory securities	0	0
Level I [Member] | Unit investment trusts [Member]
Inventory securities:
Total inventory securities		2
Level I [Member] | Other [Member]
Inventory securities:
Total inventory securities	1	0
Investment securities:
Total investment securities	0	0
Level I [Member] | Mutual funds [Member]
Investment securities:
Total investment securities	113	116
Level I [Member] | Government and agency obligations [Member]
Investment securities:
Total investment securities	19	19
Level I [Member] | U.S. treasuries [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	1,152	1,154
Level I [Member] | Equities [Member]
Inventory securities:
Total inventory securities	37	27
Investment securities:
Total investment securities	5	5
Level I [Member] | Corporate bonds and notes [Member]
Inventory securities:
Total inventory securities	0	0
Level I [Member] | Certificates of deposit [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	0	0
Inventory securities:
Total inventory securities		0
Level II [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	225	225
Inventory securities:
Total inventory securities	58	73
Investment securities:
Total investment securities	1	1
Level II [Member] | State and municipal obligations [Member]
Inventory securities:
Total inventory securities	54	67
Level II [Member] | Unit investment trusts [Member]
Inventory securities:
Total inventory securities		0
Level II [Member] | Other [Member]
Inventory securities:
Total inventory securities	1	1
Investment securities:
Total investment securities	1	1
Level II [Member] | Mutual funds [Member]
Investment securities:
Total investment securities	0	0
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] | Equities [Member]
Inventory securities:
Total inventory securities	0	0
Investment securities:
Total investment securities	0	0
Level II [Member] | Corporate bonds and notes [Member]
Inventory securities:
Total inventory securities	3	3
Level II [Member] | Certificates of deposit [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	225	225
Inventory securities:
Total inventory securities		2
Level III [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	0	0
Inventory securities:
Total inventory securities	0	0
Investment securities:
Total investment securities	0	0
Level III [Member] | State and municipal obligations [Member]
Inventory securities:
Total inventory securities	0	0
Level III [Member] | Unit investment trusts [Member]
Inventory securities:
Total inventory securities		0
Level III [Member] | Other [Member]
Inventory securities:
Total inventory securities	0	0
Investment securities:
Total investment securities	0	0
Level III [Member] | Mutual funds [Member]
Investment securities:
Total investment securities	0	0
Level III [Member] | Government and agency obligations [Member]
Investment securities:
Total investment securities	0	0
Level III [Member] | U.S. treasuries [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	0	0
Level III [Member] | Equities [Member]
Inventory securities:
Total inventory securities	0	0
Investment securities:
Total investment securities	0	0
Level III [Member] | Corporate bonds and notes [Member]
Inventory securities:
Total inventory securities	0	0
Level III [Member] | Certificates of deposit [Member]
Investments segregated under federal regulations:
Total investments segregated under federal regulations	0	0
Inventory securities:
Total inventory securities		$ 0