Cash and Cash Equivalents and Short-term Investments	9 Months Ended
Sep. 30, 2014
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Cash and Cash Equivalents and Short-term Investments	Cash and Cash Equivalents and Short-term Investments Cash and cash equivalents include cash balances and all highly liquid investments with initial maturities of three months or less. Short-term investments include certificates of deposit, money market funds and highly liquid debt instruments purchased with initial maturities in excess of three months but less than one year and are carried at amortized cost, which approximates fair value. At September 30, 2014, Cash and cash equivalents and Short-term investments were $599 million compared to $1.0 billion at December 31, 2013. Of the total balance, $144 million and $214 million was restricted as to its use at September 30, 2014 and December 31, 2013, respectively. Included within that amount, at September 30, 2014, the Company is required to hold £40.5 million of operating funds in the U.K. by the Financial Conduct Authority, a U.K.-based regulator, which were included in Short-term investments. At December 31, 2013, the Company was required to hold £77 million of operating funds in Short-term investments. These operating funds, when translated to U.S. dollars, were equal to $66 million and $126 million at September 30, 2014 and December 31, 2013, respectively. In addition, Cash and cash equivalents included additional restricted balances of $78 million and $88 million at September 30, 2014 and December 31, 2013, respectively. The restricted balances primarily relate to cash required to be held as collateral.

Cash and Cash Equivalents and Short-term Investments

Cash and cash equivalents include cash balances and all highly liquid investments with initial maturities of three months or less. Short-term investments include certificates of deposit, money market funds and highly liquid debt instruments purchased with initial maturities in excess of three months but less than one year and are carried at amortized cost, which approximates fair value.

At September 30, 2014, Cash and cash equivalents and Short-term investments were $599 million compared to $1.0 billion at December 31, 2013. Of the total balance, $144 million and $214 million was restricted as to its use at September 30, 2014 and December 31, 2013, respectively. Included within that amount, at September 30, 2014, the Company is required to hold £40.5 million of operating funds in the U.K. by the Financial Conduct Authority, a U.K.-based regulator, which were included in Short-term investments. At December 31, 2013, the Company was required to hold £77 million of operating funds in Short-term investments. These operating funds, when translated to U.S. dollars, were equal to $66 million and $126 million at September 30, 2014 and December 31, 2013, respectively. In addition, Cash and cash equivalents included additional restricted balances of $78 million and $88 million at September 30, 2014 and December 31, 2013, respectively. The restricted balances primarily relate to cash required to be held as collateral.