Derivative Instruments (Details) (USD $) In Billions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Interest rate contract	Dec. 31, 2012 Interest rate contract	Sep. 30, 2013 Credit derivatives	Dec. 31, 2012 Credit derivatives	Sep. 30, 2013 Foreign exchange	Dec. 31, 2012 Foreign exchange	Sep. 30, 2013 Equity	Dec. 31, 2012 Equity	Sep. 30, 2013 Commodity	Dec. 31, 2012 Commodity	Sep. 30, 2013 Swap Interest rate contract	Dec. 31, 2012 Swap Interest rate contract	Sep. 30, 2013 Swap Equity	Dec. 31, 2012 Swap Equity	Sep. 30, 2013 Swap Commodity	Dec. 31, 2012 Swap Commodity	Sep. 30, 2013 Future and forwards Interest rate contract	Dec. 31, 2012 Future and forwards Interest rate contract	Sep. 30, 2013 Future and forwards Equity	Dec. 31, 2012 Future and forwards Equity	Sep. 30, 2013 Written options Interest rate contract	Dec. 31, 2012 Written options Interest rate contract	Sep. 30, 2013 Written options Foreign exchange	Dec. 31, 2012 Written options Foreign exchange	Sep. 30, 2013 Written options Equity	Dec. 31, 2012 Written options Equity	Sep. 30, 2013 Written options Commodity	Dec. 31, 2012 Written options Commodity	Sep. 30, 2013 Purchased options Interest rate contract	Dec. 31, 2012 Purchased options Interest rate contract	Sep. 30, 2013 Purchased options Foreign exchange	Dec. 31, 2012 Purchased options Foreign exchange	Sep. 30, 2013 Purchased options Equity	Dec. 31, 2012 Purchased options Equity	Sep. 30, 2013 Purchased options Commodity	Dec. 31, 2012 Purchased options Commodity	Sep. 30, 2013 Cross-currency swaps Foreign exchange	Dec. 31, 2012 Cross-currency swaps Foreign exchange	Sep. 30, 2013 Spot futures and forwards Foreign exchange	Dec. 31, 2012 Spot futures and forwards Foreign exchange	Sep. 30, 2013 Spot futures and forwards Commodity	Dec. 31, 2012 Spot futures and forwards Commodity	Jul. 02, 2012 Chief Investment Office Synthetic Credit Derivatives Credit derivatives
Notional amount of derivative contracts outstanding [Abstract]
Total derivative notional amounts	$ 73,862.0	$ 69,546.0	$ 56,980.0	$ 52,730.0	$ 5,944.0	$ 5,981.0	$ 8,959.0	$ 8,754.0	$ 1,125.0	$ 1,057.0	$ 854.0	$ 1,024.0	$ 36,411.0	$ 33,129.0	$ 204.0	$ 163.0	$ 256.0	$ 312.0	$ 12,124.0	$ 11,824.0	$ 45.0	$ 49.0	$ 4,164.0	$ 3,866.0	$ 733.0	$ 651.0	$ 414.0	$ 442.0	$ 239.0	$ 262.0	$ 4,281.0	$ 3,911.0	$ 726.0	$ 661.0	$ 462.0	$ 403.0	$ 226.0	$ 260.0	$ 3,544.0	$ 3,409.0	$ 3,956.0	$ 4,033.0	$ 133.0	$ 190.0	$ 12.0