Net Capital Requirements - Partnership's Net Capital Figures for U.S. and Canada Broker-Dealer Subsidiaries (Detail) - USD ($) $ in Millions	Sep. 28, 2018	Dec. 31, 2017
United States [Member]
Regulatory Capital Requirements
Net capital	$ 1,061	$ 1,107
Net capital in excess of the minimum required	$ 1,001	$ 1,049
Net capital as a percentage of aggregate debit items	35.20%	38.10%
Net capital after anticipated capital withdrawals, as a percentage of aggregate debit items	18.60%	21.60%
Canada [Member]
Regulatory Capital Requirements
Regulatory risk-adjusted capital	$ 40	$ 50
Regulatory risk-adjusted capital in excess of the minimum required to be held by IIROC	$ 35	$ 42