Derivative Instruments and Hedging Activities - Notionals of Derivative Contracts (Details) - USD ($) $ in Billions	Mar. 31, 2021	Dec. 31, 2020
Derivatives, Notional Amount
Derivative assets	$ 17,561	$ 15,706
Derivative liabilities	17,808	16,280
Bilateral OTC
Derivatives, Notional Amount
Derivative assets	8,557	7,592
Derivative liabilities	8,736	7,901
Cleared OTC
Derivatives, Notional Amount
Derivative assets	7,915	7,260
Derivative liabilities	7,695	7,198
Exchange- Traded
Derivatives, Notional Amount
Derivative assets	1,089	854
Derivative liabilities	1,377	1,181
Designated as accounting hedges
Derivatives, Notional Amount
Derivative assets	134	131
Derivative liabilities	89	94
Designated as accounting hedges | Interest rate
Derivatives, Notional Amount
Derivative assets	121	129
Derivative liabilities	86	80
Designated as accounting hedges | Foreign exchange
Derivatives, Notional Amount
Derivative assets	13	2
Derivative liabilities	3	14
Designated as accounting hedges | Bilateral OTC
Derivatives, Notional Amount
Derivative assets	16	8
Derivative liabilities	1	11
Designated as accounting hedges | Bilateral OTC | Interest rate
Derivatives, Notional Amount
Derivative assets	4	6
Derivative liabilities	0	0
Designated as accounting hedges | Bilateral OTC | Foreign exchange
Derivatives, Notional Amount
Derivative assets	12	2
Derivative liabilities	1	11
Designated as accounting hedges | Cleared OTC
Derivatives, Notional Amount
Derivative assets	118	123
Derivative liabilities	88	83
Designated as accounting hedges | Cleared OTC | Interest rate
Derivatives, Notional Amount
Derivative assets	117	123
Derivative liabilities	86	80
Designated as accounting hedges | Cleared OTC | Foreign exchange
Derivatives, Notional Amount
Derivative assets	1	0
Derivative liabilities	2	3
Designated as accounting hedges | Exchange- Traded
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	0	0
Designated as accounting hedges | Exchange- Traded | Interest rate
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	0	0
Designated as accounting hedges | Exchange- Traded | Foreign exchange
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	0	0
Not designated as accounting hedges
Derivatives, Notional Amount
Derivative assets	17,427	15,575
Derivative liabilities	17,719	16,186
Not designated as accounting hedges | Bilateral OTC
Derivatives, Notional Amount
Derivative assets	8,541	7,584
Derivative liabilities	8,735	7,890
Not designated as accounting hedges | Cleared OTC
Derivatives, Notional Amount
Derivative assets	7,797	7,137
Derivative liabilities	7,607	7,115
Not designated as accounting hedges | Exchange- Traded
Derivatives, Notional Amount
Derivative assets	1,089	854
Derivative liabilities	1,377	1,181
Economic loan hedges | Credit
Derivatives, Notional Amount
Derivative assets	0	1
Derivative liabilities	8	6
Economic loan hedges | Bilateral OTC | Credit
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	1	1
Economic loan hedges | Cleared OTC | Credit
Derivatives, Notional Amount
Derivative assets	0	1
Derivative liabilities	7	5
Economic loan hedges | Exchange- Traded | Credit
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	0	0
Other derivatives | Interest rate
Derivatives, Notional Amount
Derivative assets	12,460	11,202
Derivative liabilities	12,352	11,426
Other derivatives | Credit
Derivatives, Notional Amount
Derivative assets	332	227
Derivative liabilities	336	235
Other derivatives | Foreign exchange
Derivatives, Notional Amount
Derivative assets	3,587	3,159
Derivative liabilities	3,652	3,293
Other derivatives | Equity
Derivatives, Notional Amount
Derivative assets	855	811
Derivative liabilities	1,191	1,065
Other derivatives | Commodity and other
Derivatives, Notional Amount
Derivative assets	193	175
Derivative liabilities	180	161
Other derivatives | Bilateral OTC | Interest rate
Derivatives, Notional Amount
Derivative assets	4,292	3,847
Derivative liabilities	4,361	4,000
Other derivatives | Bilateral OTC | Credit
Derivatives, Notional Amount
Derivative assets	198	140
Derivative liabilities	200	142
Other derivatives | Bilateral OTC | Foreign exchange
Derivatives, Notional Amount
Derivative assets	3,479	3,046
Derivative liabilities	3,544	3,180
Other derivatives | Bilateral OTC | Equity
Derivatives, Notional Amount
Derivative assets	453	444
Derivative liabilities	527	474
Other derivatives | Bilateral OTC | Commodity and other
Derivatives, Notional Amount
Derivative assets	119	107
Derivative liabilities	102	93
Other derivatives | Cleared OTC | Interest rate
Derivatives, Notional Amount
Derivative assets	7,562	6,946
Derivative liabilities	7,366	6,915
Other derivatives | Cleared OTC | Credit
Derivatives, Notional Amount
Derivative assets	134	87
Derivative liabilities	136	93
Other derivatives | Cleared OTC | Foreign exchange
Derivatives, Notional Amount
Derivative assets	101	103
Derivative liabilities	98	102
Other derivatives | Cleared OTC | Equity
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	0	0
Other derivatives | Cleared OTC | Commodity and other
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	0	0
Other derivatives | Exchange- Traded | Interest rate
Derivatives, Notional Amount
Derivative assets	606	409
Derivative liabilities	625	511
Other derivatives | Exchange- Traded | Credit
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	0	0
Other derivatives | Exchange- Traded | Foreign exchange
Derivatives, Notional Amount
Derivative assets	7	10
Derivative liabilities	10	11
Other derivatives | Exchange- Traded | Equity
Derivatives, Notional Amount
Derivative assets	402	367
Derivative liabilities	664	591
Other derivatives | Exchange- Traded | Commodity and other
Derivatives, Notional Amount
Derivative assets	74	68
Derivative liabilities	$ 78	$ 68