Fair Value of Financial Instruments (Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis Additional Information) (Details) (USD $)
In Millions, unless otherwise specified

Sep. 30, 2013

Dec. 31, 2012

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial investments, at fair value

$ 190

^[1]

$ 223

^[1]

Default fund investments

1,910

^[2]

175

^[2]

Default funds and margin deposits

1,934

209

Foreign Government Debt Securities [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial investments, at fair value

145

201

Restricted assets [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial investments, at fair value

102

134

Available-for-sale Securities [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial investments, at fair value

US Government Debt Securities [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Default fund investments

$ 175

[1]

Primarily comprised of trading securities, mainly Swedish government debt securities, of $145 million as of September 30, 2013 and $201 million as of December 31, 2012. Of these securities, $102 million as of September 30, 2013 and $134 million as of December 31, 2012 are assets utilized to meet regulatory capital requirements primarily for clearing operations at NASDAQ OMX Nordic Clearing. This balance also includes our available-for-sale investment security in DFM valued at $45 million as of September 30, 2013 and $22 million as of December 31, 2012. See Note 6, “Investments,” for further discussion of our trading investment securities and available-for-sale investment security.

[2]

Default fund and margin deposit investments include cash contributions invested by NASDAQ OMX Nordic Clearing, in accordance with its investment policy, either in highly rated government debt securities or reverse repurchase agreements with highly rated government debt securities as collateral. Of the total balance of $1,934 million recorded in the Condensed Consolidated Balance Sheets as of September 30, 2013, $1,229 million of cash contributions have been invested in reverse repurchase agreements and $681 million of cash contributions have been invested in highly rated government debt securities and term deposits. The remainder of this balance is held in cash. As of December 31, 2012, $175 million of cash contributions were invested in highly rated government debt securities. See Note 14, “Clearing Operations,” for further discussion of default fund contributions and margin deposits.

- Definition

In anticipation of new regulations proposed by the European Market Infrastructure Regulation, NASDAQ OMX Nordic Clearing implemented three member sponsored default funds in March 2012: one related to financial markets, one related to commodities markets, and a mutualized fund. Under this new regulatory structure, NASDAQ OMX Nordic Clearing and its clearing members must contribute to the total regulatory capital related to the clearing operations of NASDAQ OMX Nordic Clearing. This new requirement ensures the alignment of risk between NASDAQ OMX Nordic Clearing and its clearing members. Contributions made to the default funds will be proportional to the exposures of each clearing member. This structure applies an initial separation of default fund contributions for the financial and commodities markets in order to create a buffer for each market's counterparty risks. Simultaneously, a mutualized default fund provides capital efficiencies with regard to total regulatory capital required. When a clearing member is active in both the financial and commodities markets, contributions must be made to both markets' default funds.Clearing members' eligible contributions may include cash and non-cash contributions. Cash contributions received are invested by NASDAQ OMX Nordic Clearing, in accordance with our investment policy, either in highly rated government debt securities or reverse repurchase agreements with highly rated government debt securities as collateral. Clearing members' cash contributions are included in default funds and margin deposits in the Condensed Consolidated Balance Sheets as both a current asset and a current liability.

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