Guarantees	9 Months Ended
Sep. 30, 2012
Guarantees [Abstract]
Guarantees	Guarantees Clearing House Contract Settlement. CME and CME Clearing Europe (CMECE) mark-to-market open positions for most products at least twice a day. Based on values derived from the mark-to-market process, CME and CMECE require payment from clearing firms whose positions have lost value and make payments to clearing firms whose positions have gained value. For select cleared-only markets, positions are marked-to-market once daily, with the capability to mark-to-market more frequently as market conditions warrant. Under the extremely unlikely scenario of simultaneous default by every clearing firm who has open positions with unrealized losses, the maximum exposure related to CME and CMECE’s guarantee would be one half day of changes in fair value of all open positions, before considering CME and CMECE’s ability to access defaulting clearing firms’ performance bond and guaranty fund balances as well as other available resources. During the first nine months of 2012, CME and CMECE transferred an average of approximately $2.5 billion a day through their clearing systems for settlement from clearing firms whose positions had lost value to clearing firms whose positions had gained value. CME and CMECE reduce the guarantee exposure through initial and maintenance performance bond requirements and mandatory guaranty fund contributions. The company believes that its guarantee liability is immaterial and therefore has not recorded any liability at September 30, 2012. Mutual Offset Agreement. CME and Singapore Exchange Limited (SGX) have a mutual offset agreement with a current term through October 2013. The term of the agreement will automatically renew for a one-year period unless either party provides advance notice of their intent to terminate. CME can maintain collateral in the form of U.S. Treasury securities or irrevocable letters of credit. At September 30, 2012, CME was contingently liable to SGX on irrevocable letters of credit totaling $196.0 million. Regardless of the collateral, CME guarantees all cleared transactions submitted through SGX and would initiate procedures designed to satisfy these financial obligations in the event of a default, such as the use of performance bonds and guaranty fund contributions of the defaulting clearing firm. Cross-Margin Agreements. CME and The Options Clearing Corporation (OCC) have a cross-margin arrangement, whereby a common clearing firm may maintain a cross-margin account in which the clearing firm's positions in certain CME futures and options on futures contracts are combined with certain positions cleared by OCC for purposes of calculating performance bond requirements. The performance bond deposits are held jointly by CME and OCC. If a participating firm defaults, the gain or loss on the liquidation of the firm's open position and the proceeds from the liquidation of the cross-margin account would be allocated 50% each to CME and OCC. A cross-margin agreement exists with CME and Fixed Income Clearing Corp (FICC) whereby the clearing firms' offsetting positions with CME are subject to reduced margin requirements. Clearing firms maintain separate performance bond deposits with each clearing house, but depending on the net offsetting positions between CME and FICC, each clearing house may reduce the firm's performance bond requirement. In the event of a firm default, the total liquidation net gain or loss on the firm's offsetting open positions and the proceeds from the liquidation of the performance bond collateral held by each clearing house's supporting offsetting positions would be divided evenly between CME and FICC. Additionally, if, after liquidation of all the positions and collateral of the defaulting firm at each respective clearing organization, and taking into account any cross-margining loss sharing payments, any of the participating clearing organizations has a remaining liquidating surplus, and any other participating clearing organization has a remaining liquidating deficit, any additional surplus from the liquidation would be shared with the other clearing house to the extent that it has a remaining liquidating deficit. Any remaining surplus funds would be passed to the bankruptcy trustee. MF Global Bankruptcy Guarantee. The company has provided a $550.0 million financial guarantee to the bankruptcy trustee of MF Global in order to accelerate the distribution of funds to MF Global customers. In the event that the trustee distributed more property than was permitted by the Bankruptcy Code and CFTC regulations to any former MF Global customer on or after November 16, 2011, the company will make a cash payment for the amount of the erroneous distribution up to $550.0 million to the trustee. A payment will only be made after the trustee makes reasonable efforts to collect the property erroneously distributed to the customer. If a payment is made by the company, the company may have the right to seek reimbursement of the erroneously distributed property from the applicable customer. The guarantee only applies to the second and third bulk distributions that were facilitated by the company. The guarantee does not cover future distributions made directly by the trustee to customers. The company believes that the likelihood of payment to the trustee is remote given the process in place to validate customer distributions. As a result, the guarantee liability is estimated to be immaterial at September 30, 2012. Family Farmer and Rancher Protection Fund. In April 2012, the company established the Family Farmer and Rancher Protection Fund (the Fund). The Fund is designed to provide payments, up to certain maximum levels, to family farmers, ranchers and other agricultural industry participants who use CME Group agricultural products and who suffer losses to their segregated account balances when their CME clearing member becomes insolvent. Under the terms of the Fund, farmers and ranchers are eligible for up to $25,000 per participant. Farming and ranching cooperatives are eligible for up to $100,000 per cooperative. The Fund has an aggregate maximum payment amount of $100.0 million. If payments to participants were to exceed this amount, payments would be pro-rated. Clearing members and customers must register in advance with the company and provide certain documentation in order to substantiate their eligibility. Peregrine Financial Group, Inc. (PFG) filed for bankruptcy protection on July 10, 2012. PFG was not a CME clearing member and its customers had not registered for the Fund. Accordingly, they were not technically eligible for payments. However, because the Fund was newly implemented and because PFG's customers included many agricultural industry participants for whom the program was designed, the company decided to waive certain terms and conditions of the Fund, solely in connection with the PFG bankruptcy, so that otherwise eligible family farmers, ranchers and agricultural cooperatives could apply for and receive benefits from CME. Based on the number of such PFG customers who applied and the estimated size of their claims, the company has recorded a liability in the amount of $2.2 million at September 30, 2012.

Guarantees

Clearing House Contract Settlement. CME and CME Clearing Europe (CMECE) mark-to-market open positions for most products at least twice a day. Based on values derived from the mark-to-market process, CME and CMECE require payment from clearing firms whose positions have lost value and make payments to clearing firms whose positions have gained value. For select cleared-only markets, positions are marked-to-market once daily, with the capability to mark-to-market more frequently as market conditions warrant. Under the extremely unlikely scenario of simultaneous default by every clearing firm who has open positions with unrealized losses, the maximum exposure related to CME and CMECE’s guarantee would be one half day of changes in fair value of all open positions, before considering CME and CMECE’s ability to access defaulting clearing firms’ performance bond and guaranty fund balances as well as other available resources. During the first nine months of 2012, CME and CMECE transferred an average of approximately $2.5 billion a day through their clearing systems for settlement from clearing firms whose positions had lost value to clearing firms whose positions had gained value. CME and CMECE reduce the guarantee exposure through initial and maintenance performance bond requirements and mandatory guaranty fund contributions. The company believes that its guarantee liability is immaterial and therefore has not recorded any liability at September 30, 2012.

Mutual Offset Agreement. CME and Singapore Exchange Limited (SGX) have a mutual offset agreement with a current term through October 2013. The term of the agreement will automatically renew for a one-year period unless either party provides advance notice of their intent to terminate. CME can maintain collateral in the form of U.S. Treasury securities or irrevocable letters of credit. At September 30, 2012, CME was contingently liable to SGX on irrevocable letters of credit totaling $196.0 million. Regardless of the collateral, CME guarantees all cleared transactions submitted through SGX and would initiate procedures designed to satisfy these financial obligations in the event of a default, such as the use of performance bonds and guaranty fund contributions of the defaulting clearing firm.

Cross-Margin Agreements. CME and The Options Clearing Corporation (OCC) have a cross-margin arrangement, whereby a common clearing firm may maintain a cross-margin account in which the clearing firm's positions in certain CME futures and options on futures contracts are combined with certain positions cleared by OCC for purposes of calculating performance bond requirements. The performance bond deposits are held jointly by CME and OCC. If a participating firm defaults, the gain or loss on the liquidation of the firm's open position and the proceeds from the liquidation of the cross-margin account would be allocated 50% each to CME and OCC.

A cross-margin agreement exists with CME and Fixed Income Clearing Corp (FICC) whereby the clearing firms' offsetting positions with CME are subject to reduced margin requirements. Clearing firms maintain separate performance bond deposits with each clearing house, but depending on the net offsetting positions between CME and FICC, each clearing house may reduce the firm's performance bond requirement. In the event of a firm default, the total liquidation net gain or loss on the firm's offsetting open positions and the proceeds from the liquidation of the performance bond collateral held by each clearing house's supporting offsetting positions would be divided evenly between CME and FICC. Additionally, if, after liquidation of all the positions and collateral of the defaulting firm at each respective clearing organization, and taking into account any cross-margining loss sharing payments, any of the participating clearing organizations has a remaining liquidating surplus, and any other participating clearing organization has a remaining liquidating deficit, any additional surplus from the liquidation would be shared with the other clearing house to the extent that it has a remaining liquidating deficit. Any remaining surplus funds would be passed to the bankruptcy trustee.

MF Global Bankruptcy Guarantee. The company has provided a $550.0 million financial guarantee to the bankruptcy trustee of MF Global in order to accelerate the distribution of funds to MF Global customers. In the event that the trustee distributed more property than was permitted by the Bankruptcy Code and CFTC regulations to any former MF Global customer on or after November 16, 2011, the company will make a cash payment for the amount of the erroneous distribution up to $550.0 million to the trustee. A payment will only be made after the trustee makes reasonable efforts to collect the property erroneously distributed to the customer. If a payment is made by the company, the company may have the right to seek reimbursement of the erroneously distributed property from the applicable customer. The guarantee only applies to the second and third bulk distributions that were facilitated by the company. The guarantee does not cover future distributions made directly by the trustee to customers. The company believes that the likelihood of payment to the trustee is remote given the process in place to validate customer distributions. As a result, the guarantee liability is estimated to be immaterial at September 30, 2012.

Family Farmer and Rancher Protection Fund. In April 2012, the company established the Family Farmer and Rancher Protection Fund (the Fund). The Fund is designed to provide payments, up to certain maximum levels, to family farmers, ranchers and other agricultural industry participants who use CME Group agricultural products and who suffer losses to their segregated account balances when their CME clearing member becomes insolvent. Under the terms of the Fund, farmers and ranchers are eligible for up to $25,000 per participant. Farming and ranching cooperatives are eligible for up to $100,000 per cooperative. The Fund has an aggregate maximum payment amount of $100.0 million. If payments to participants were to exceed this amount, payments would be pro-rated. Clearing members and customers must register in advance with the company and provide certain documentation in order to substantiate their eligibility.

Peregrine Financial Group, Inc. (PFG) filed for bankruptcy protection on July 10, 2012. PFG was not a CME clearing member and its customers had not registered for the Fund. Accordingly, they were not technically eligible for payments. However, because the Fund was newly implemented and because PFG's customers included many agricultural industry participants for whom the program was designed, the company decided to waive certain terms and conditions of the Fund, solely in connection with the PFG bankruptcy, so that otherwise eligible family farmers, ranchers and agricultural cooperatives could apply for and receive benefits from CME. Based on the number of such PFG customers who applied and the estimated size of their claims, the company has recorded a liability in the amount of $2.2 million at September 30, 2012.