Derivative Instruments (Details) (USD $) In Billions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	$ 73,332	$ 71,156
Foreign exchange
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	9,351	8,787
Equity
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	1,191	1,022
Credit derivatives
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	6,164	5,774
Commodity
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	1,220	1,113
Interest rate contract
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	55,406	54,460
Swap [Member] | Equity
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	131	119
Swap [Member] | Commodity
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	346	341
Swap [Member] | Interest rate contract
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	37,382	38,704
Spot futures and forwards [Member] | Foreign exchange
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	4,707	4,512
Spot futures and forwards [Member] | Commodity
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	216	188
Written options [Member] | Foreign exchange
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	711	674
Written options [Member] | Equity
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	527	460
Written options [Member] | Commodity
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	347	310
Written options [Member] | Interest rate contract
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	4,005	3,842
Future and forwards [Member] | Equity
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	51	38
Future and forwards [Member] | Interest rate contract
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	9,917	7,888
Purchased options [Member] | Foreign exchange
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	722	670
Purchased options [Member] | Equity
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	482	405
Purchased options [Member] | Commodity
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	311	274
Purchased options [Member] | Interest rate contract
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	4,102	4,026
Cross-currency swaps [Member] | Foreign exchange
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	$ 3,211	$ 2,931