Securities Financing Activities - Gross and Net Amounts of Securities Financing Agreements (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Assets
Securities purchased under resale agreements, Gross amounts	$ 604,201	$ 523,308
Securities purchased under resale agreements, Amounts netted on the Consolidated balance sheets	(273,642)	(247,181)
Securities purchased under resale agreements, Amounts presented on the Consolidated balance sheets	330,559	276,127
Securities purchased under resale agreements, Amounts not nettable on the Consolidated balance sheets	(322,889)	(267,582)
Securities purchased under resale agreements, Net amounts	7,670	8,545
Securities borrowed, Gross amounts	245,443	244,046
Securities borrowed, Amounts netted on the Consolidated balance sheets	(47,107)	(43,610)
Securities borrowed, Amounts presented on the Consolidated balance sheets	198,336	200,436
Securities borrowed, Amounts not nettable on the Consolidated balance sheets	(148,169)	(144,543)
Securities borrowed, Net amounts	50,167	55,893
Liabilities
Securities sold under repurchase agreements, Gross amounts	595,265	459,985
Securities sold under repurchase agreements, Amounts netted on the Consolidated balance sheets	(273,642)	(247,181)
Securities sold under repurchase agreements, Amounts presented on the Consolidated balance sheets	321,623	212,804
Securities sold under repurchase agreements, Amounts not nettable on the Consolidated balance sheets	(284,587)	(182,011)
Securities sold under repurchase agreements, Net amounts	37,036	30,793
Securities loaned and other, Gross amounts	58,708	52,142
Securities loaned and other, Amounts netted on the Consolidated balance sheets	(47,107)	(43,610)
Securities loaned and other, Amounts presented on the Consolidated balance sheets	11,601	8,532
Securities loaned and other, Amounts not nettable on the Consolidated balance sheets	(11,369)	(8,501)
Securities loaned and other, Net amounts	232	31
Securities purchased under resale agreements where an appropriate legal opinion with respect to the master netting agreement has not been either sought or obtained	5,500	7,100
where an appropriate legal opinion with respect to the master netting agreement has not been either sought or obtained	45,600	50,700
Securities sold under agreements to repurchase where an appropriate legal opinion with respect to the master netting agreement has not been either sought or obtained	36,200	30,000
Securities-for-securities
Liabilities
Securities loaned and other, Amounts presented on the Consolidated balance sheets	$ 8,900	$ 5,600