Net Capital Requirements - Partnership's Capital Figures for U.S. and Canada Broker-Dealer Subsidiaries (Detail) - USD ($) $ in Millions	Mar. 29, 2019	Dec. 31, 2018
United States [Member]
Regulatory Capital Requirements
Net capital	$ 1,372	$ 1,280
Net capital in excess of the minimum required	$ 1,315	$ 1,221
Net capital as a percentage of aggregate debit items	48.10%	43.60%
Net capital after anticipated capital withdrawals, as a percentage of aggregate debit items	28.80%	28.30%
Canada [Member]
Regulatory Capital Requirements
Regulatory risk-adjusted capital	$ 35	$ 40
Regulatory risk-adjusted capital in excess of the minimum required to be held by IIROC	$ 24	$ 39