Securities Financing Activities - Gross and Net Amounts of Securities Financing Agreements (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Assets
Securities purchased under resale agreements, Gross amounts	$ 695,230	$ 523,308
Securities purchased under resale agreements, Amounts netted on the Consolidated balance sheets	(304,409)	(247,181)
Securities purchased under resale agreements, Amounts presented on the Consolidated balance sheets	390,821	276,127
Securities purchased under resale agreements, Amounts not nettable on the Consolidated balance sheets	(376,898)	(267,582)
Securities purchased under resale agreements, Net amounts	13,923	8,545
Securities borrowed, Gross amounts	305,198	244,046
Securities borrowed, Amounts netted on the Consolidated balance sheets	(52,764)	(43,610)
Securities borrowed, Amounts presented on the Consolidated balance sheets	252,434	200,436
Securities borrowed, Amounts not nettable on the Consolidated balance sheets	(191,878)	(144,543)
Securities borrowed, Net amounts	60,556	55,893
Liabilities
Securities sold under repurchase agreements, Gross amounts	688,549	459,985
Securities sold under repurchase agreements, Amounts netted on the Consolidated balance sheets	(304,409)	(247,181)
Securities sold under repurchase agreements, Amounts presented on the Consolidated balance sheets	384,140	212,804
Securities sold under repurchase agreements, Amounts not nettable on the Consolidated balance sheets	(339,430)	(182,011)
Securities sold under repurchase agreements, Net amounts	44,710	30,793
Securities loaned and other, Gross amounts	63,109	52,142
Securities loaned and other, Amounts netted on the Consolidated balance sheets	(52,764)	(43,610)
Securities loaned and other, Amounts presented on the Consolidated balance sheets	10,345	8,532
Securities loaned and other, Amounts not nettable on the Consolidated balance sheets	(10,230)	(8,501)
Securities loaned and other, Net amounts	115	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	10,800	7,100
Securities borrowed where an appropriate legal opinion with respect to the master netting agreement has not been either sought or obtained	53,300	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	43,900	30,000
Securities-for-securities
Liabilities
Securities loaned and other, Amounts presented on the Consolidated balance sheets	$ 5,800	$ 5,600