Schedule I - Condensed Statements of Financial Condition (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
ASSETS:
Cash and cash equivalents	$ 1,125	$ 1,014	$ 1,498
Investment securities	1,302	332
Other assets	149	156
TOTAL ASSETS	28,320	19,317	15,815
LIABILITIES:
Accounts payable, accrued expenses and other	352	351
Partnership capital subject to mandatory redemption	3,589	3,364	$ 2,855	$ 2,795
TOTAL LIABILITIES	28,320	19,317
Parent Company [Member]
ASSETS:
Cash and cash equivalents	323	320
Investment securities	3	2
Investment in subsidiaries	3,356	3,109
Other assets	55	49
TOTAL ASSETS	3,737	3,480
LIABILITIES:
Accounts payable, accrued expenses and other	148	116
Partnership capital subject to mandatory redemption	3,589	3,364
TOTAL LIABILITIES	$ 3,737	$ 3,480