Other Assets - Other Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Other Assets [Abstract]
Property, leasehold improvements and equipment	$ 23,515	$ 21,886
Goodwill and identifiable intangible assets	4,965	4,837
Operating lease right-of-use assets	2,268	2,360
Income tax-related assets	2,543	2,068
Miscellaneous receivables and other	4,683	3,731
Total	$ 37,974	$ 34,882