Securities Financing Activities - Gross and Net Amounts of Securities Financing Agreements (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Assets
Securities purchased under resale agreements, Gross amounts	$ 556,708	$ 597,912
Securities purchased under resale agreements, Amounts netted on the Consolidated balance sheets	(206,711)	(282,411)
Securities purchased under resale agreements, Amounts presented on the Consolidated balance sheets	349,997	315,501
Securities purchased under resale agreements, Amounts not nettable on the Consolidated balance sheets	(339,936)	(304,120)
Securities purchased under resale agreements, Net amounts	10,061	11,381
Securities borrowed, Gross amounts	226,710	228,279
Securities borrowed, Amounts netted on the Consolidated balance sheets	(38,431)	(42,910)
Securities borrowed, Amounts presented on the Consolidated balance sheets	188,279	185,369
Securities borrowed, Amounts not nettable on the Consolidated balance sheets	(137,150)	(131,578)
Securities borrowed, Net amounts	51,129	53,791
Liabilities
Securities sold under repurchase agreements, Gross amounts	467,094	480,793
Securities sold under repurchase agreements, Amounts netted on the Consolidated balance sheets	(206,711)	(282,411)
Securities sold under repurchase agreements, Amounts presented on the Consolidated balance sheets	260,383	198,382
Securities sold under repurchase agreements, Amounts not nettable on the Consolidated balance sheets	(224,365)	(167,427)
Securities sold under repurchase agreements, Net amounts	36,018	30,955
Securities loaned and other, Gross amounts	49,530	52,443
Securities loaned and other, Amounts netted on the Consolidated balance sheets	(38,431)	(42,910)
Securities loaned and other, Amounts presented on the Consolidated balance sheets	11,099	9,533
Securities loaned and other, Amounts not nettable on the Consolidated balance sheets	(10,866)	(9,527)
Securities loaned and other, Net amounts	233	6
Securities purchased under resale agreements where an appropriate legal opinion has not been either sought or obtained, Gross asset balance	6,200	6,000
Securities borrowed where an appropriate legal opinion has not been either sought or obtained	46,700	49,000
Securities sold under agreements to repurchase	34,100	29,100
Securities loaned and other	105	2
Securities-for-securities
Liabilities
Securities loaned and other, Amounts presented on the Consolidated balance sheets	$ 4,400	$ 7,000