Transactions with Affiliated Funds - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Mar. 31, 2020	Dec. 31, 2019
Transactions With Affiliated Funds [Abstract]
Management fees waived	$ 26	$ 11	$ 57	$ 32
Outstanding guarantees on behalf of certain nonconsolidated investment funds	87		87			$ 87
Fair value of certificates of deposit and commercial paper purchased	$ 439		$ 439		$ 1,840