Derivative Instruments and Hedging Activities - Notionals of Derivative Contracts (Details) - USD ($) $ in Billions	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Notional Amount
Derivative assets	$ 15,706	$ 16,461
Derivative liabilities	16,280	16,098
Bilateral OTC
Derivatives, Notional Amount
Derivative assets	7,592	7,577
Derivative liabilities	7,901	7,728
Cleared OTC
Derivatives, Notional Amount
Derivative assets	7,260	7,662
Derivative liabilities	7,198	7,114
Exchange- Traded
Derivatives, Notional Amount
Derivative assets	854	1,222
Derivative liabilities	1,181	1,256
Designated as accounting hedges
Derivatives, Notional Amount
Derivative assets	131	110
Derivative liabilities	94	82
Designated as accounting hedges | Interest rate
Derivatives, Notional Amount
Derivative assets	129	108
Derivative liabilities	80	71
Designated as accounting hedges | Foreign exchange
Derivatives, Notional Amount
Derivative assets	2	2
Derivative liabilities	14	11
Designated as accounting hedges | Bilateral OTC
Derivatives, Notional Amount
Derivative assets	8	16
Derivative liabilities	11	9
Designated as accounting hedges | Bilateral OTC | Interest rate
Derivatives, Notional Amount
Derivative assets	6	14
Derivative liabilities	0	0
Designated as accounting hedges | Bilateral OTC | Foreign exchange
Derivatives, Notional Amount
Derivative assets	2	2
Derivative liabilities	11	9
Designated as accounting hedges | Cleared OTC
Derivatives, Notional Amount
Derivative assets	123	94
Derivative liabilities	83	73
Designated as accounting hedges | Cleared OTC | Interest rate
Derivatives, Notional Amount
Derivative assets	123	94
Derivative liabilities	80	71
Designated as accounting hedges | Cleared OTC | Foreign exchange
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	3	2
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	15,575	16,351
Derivative liabilities	16,186	16,016
Not designated as accounting hedges | Interest rate
Derivatives, Notional Amount
Derivative assets	11,202	12,360
Derivative liabilities	11,426	11,717
Not designated as accounting hedges | Credit
Derivatives, Notional Amount
Derivative assets	228	215
Derivative liabilities	241	237
Not designated as accounting hedges | Foreign exchange
Derivatives, Notional Amount
Derivative assets	3,159	2,768
Derivative liabilities	3,293	2,946
Not designated as accounting hedges | Equity
Derivatives, Notional Amount
Derivative assets	811	848
Derivative liabilities	1,065	970
Not designated as accounting hedges | Commodity and other
Derivatives, Notional Amount
Derivative assets	175	160
Derivative liabilities	161	146
Not designated as accounting hedges | Bilateral OTC
Derivatives, Notional Amount
Derivative assets	7,584	7,561
Derivative liabilities	7,890	7,719
Not designated as accounting hedges | Bilateral OTC | Interest rate
Derivatives, Notional Amount
Derivative assets	3,847	4,230
Derivative liabilities	4,000	4,185
Not designated as accounting hedges | Bilateral OTC | Credit
Derivatives, Notional Amount
Derivative assets	140	136
Derivative liabilities	143	153
Not designated as accounting hedges | Bilateral OTC | Foreign exchange
Derivatives, Notional Amount
Derivative assets	3,046	2,667
Derivative liabilities	3,180	2,841
Not designated as accounting hedges | Bilateral OTC | Equity
Derivatives, Notional Amount
Derivative assets	444	429
Derivative liabilities	474	455
Not designated as accounting hedges | Bilateral OTC | Commodity and other
Derivatives, Notional Amount
Derivative assets	107	99
Derivative liabilities	93	85
Not designated as accounting hedges | Cleared OTC
Derivatives, Notional Amount
Derivative assets	7,137	7,568
Derivative liabilities	7,115	7,041
Not designated as accounting hedges | Cleared OTC | Interest rate
Derivatives, Notional Amount
Derivative assets	6,946	7,398
Derivative liabilities	6,915	6,866
Not designated as accounting hedges | Cleared OTC | Credit
Derivatives, Notional Amount
Derivative assets	88	79
Derivative liabilities	98	84
Not designated as accounting hedges | Cleared OTC | Foreign exchange
Derivatives, Notional Amount
Derivative assets	103	91
Derivative liabilities	102	91
Not designated as accounting hedges | Cleared OTC | Equity
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	0	0
Not designated as accounting hedges | Cleared OTC | Commodity and other
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	0	0
Not designated as accounting hedges | Exchange- Traded
Derivatives, Notional Amount
Derivative assets	854	1,222
Derivative liabilities	1,181	1,256
Not designated as accounting hedges | Exchange- Traded | Interest rate
Derivatives, Notional Amount
Derivative assets	409	732
Derivative liabilities	511	666
Not designated as accounting hedges | Exchange- Traded | Credit
Derivatives, Notional Amount
Derivative assets	0	0
Derivative liabilities	0	0
Not designated as accounting hedges | Exchange- Traded | Foreign exchange
Derivatives, Notional Amount
Derivative assets	10	10
Derivative liabilities	11	14
Not designated as accounting hedges | Exchange- Traded | Equity
Derivatives, Notional Amount
Derivative assets	367	419
Derivative liabilities	591	515
Not designated as accounting hedges | Exchange- Traded | Commodity and other
Derivatives, Notional Amount
Derivative assets	68	61
Derivative liabilities	$ 68	$ 61