Schedule I - Condensed Statements of Financial Condition (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASSETS:
Cash and cash equivalents	$ 1,498	$ 846	$ 1,047
Investment securities	250	258
Other assets	142	128
TOTAL ASSETS	15,815	17,176	19,424
LIABILITIES:
Accounts payable, accrued expenses and other	288	165
Partnership capital subject to mandatory redemption	2,855	2,795	$ 2,634	$ 2,610
TOTAL LIABILITIES	15,815	17,176
Parent Company [Member]
ASSETS:
Cash and cash equivalents	318	308
Investment securities	7	7
Investment in subsidiaries	2,596	2,462
Other assets	33	19
TOTAL ASSETS	2,954	2,796
LIABILITIES:
Accounts payable, accrued expenses and other	99	1
Partnership capital subject to mandatory redemption	2,855	2,795
TOTAL LIABILITIES	$ 2,954	$ 2,796