Derivative Instruments - Notional Amount of Derivative Contracts (Details) - USD ($) $ in Billions	Sep. 30, 2021	Dec. 31, 2020
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	$ 52,835	$ 47,175
Interest rate contracts
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	34,674	31,097
Swaps
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	24,116	20,990
Futures and forwards
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	3,824	3,057
Options | Written options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	3,211	3,375
Options | Purchased options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	3,523	3,675
Credit derivatives
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	1,340	1,197
Foreign exchange contracts
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	13,943	12,450
Cross-currency swaps
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	4,081	3,924
Spot, futures and forwards
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	8,268	6,871
Options | Written options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	803	830
Options | Purchased options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	791	825
Equity contracts
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	2,227	1,866
Swaps
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	628	448
Futures and forwards
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	145	140
Options | Written options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	750	668
Options | Purchased options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	704	610
Commodity contracts
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	651	565
Swaps
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	185	138
Spot, futures and forwards
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	195	198
Options | Written options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	149	124
Options | Purchased options
Notional amount of derivative contracts outstanding [Abstract]
Derivative notional amounts	$ 122	$ 105