v2.4.0.8
Clearing Operations (Schedule of Derivative Contracts Outstanding) (Details) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2014
contract
Mar. 31, 2013
contract
Clearing Operations [Line Items]    
Market value of derivative contracts $ 2,926  
Total Number of Cleared Contracts 25,179,779 27,882,196
Commodity forwards and options [Member]
    
Clearing Operations [Line Items]    
Market value of derivative contracts 2,217 [1],[2]  
Total Number of Cleared Contracts 246,134 [3] 236,276 [3]
Fixed-income options and futures [Member]
    
Clearing Operations [Line Items]    
Market value of derivative contracts 332 [2],[4]  
Total Number of Cleared Contracts 5,842,527 8,827,632
Stock options and futures [Member]
    
Clearing Operations [Line Items]    
Market value of derivative contracts 176 [2],[4]  
Total Number of Cleared Contracts 8,965,181 8,487,497
Index options and futures [Member]
    
Clearing Operations [Line Items]    
Market value of derivative contracts $ 201 [2],[4]  
Total Number of Cleared Contracts 10,125,937 10,330,791
[1] We determined the fair value of our forward contracts using standard valuation models that were based on market-based observable inputs including LIBOR rates and the spot price of the underlying instrument.
[2] We determined the fair value of our option contracts using standard valuation models that were based on market-based observable inputs including implied volatility, interest rates and the spot price of the underlying instrument.
[3] The total volume in cleared power related to commodity contracts was 429 Terawatt hours (TWh) for the three months ended March 31, 2014 and 460 TWh for the three months ended March 31, 2013.
[4] We determined the fair value of our futures contracts based upon quoted market prices and average quoted market yields.