Derivative Instruments - Notional Amount of Derivative Contracts (Details) - USD ($) $ in Billions	Jun. 30, 2021	Dec. 31, 2020
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	$ 53,589	$ 47,194
Interest rate contracts
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	36,542	31,097
Swaps
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	24,414	20,990
Futures and forwards
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	5,170	3,057
Options | Written options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	3,354	3,375
Options | Purchased options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	3,604	3,675
Credit derivatives
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	1,143	1,197
Foreign exchange contracts
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	13,140	12,450
Cross-currency swaps
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	4,088	3,924
Spot, futures and forwards
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	7,465	6,871
Options | Written options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	805	830
Options | Purchased options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	782	825
Equity contracts
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	2,122	1,885
Swaps
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	549	448
Futures and forwards
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	158	140
Options | Written options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	735	676
Options | Purchased options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	680	621
Commodity contracts
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	642	565
Swaps
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	175	138
Spot, futures and forwards
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	196	198
Options | Written options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	152	124
Options | Purchased options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	$ 119	$ 105