Subsequent Event	3 Months Ended
Mar. 31, 2013
Subsequent Events [Abstract]
Subsequent Event	17. Subsequent Events 2013 Acquisition Dutch Cash Equities and Equity Derivatives Trading Venue In April 2013, we acquired a 25% equity interest in TOM. The terms of the transaction also provide us an option to acquire an additional 25.1% of the remaining shares at a future date. This transaction delivers on our strategy to expand our derivatives presence across the European market and is part of our Market Services segment. We will account for our investment in TOM under the equity method of accounting. 2013 Proposed Acquisition Agreement to acquire eSpeed for Trading of U.S. Treasuries In April 2013, we announced an agreement with BGC to acquire eSpeed. Under the terms of the agreement, the purchase price will consist of $750 million in cash, subject to adjustment for certain pre-paid amounts and accrued costs and expenses, and contingent future issuances of NASDAQ OMX common stock approximating certain tax benefits associated with the transaction. Such contingent future issuances of NASDAQ OMX common stock will be paid ratably over 15 years if NASDAQ OMX achieves a designated revenue target in each such year, with such common stock valued based on the volume-weighted average price of NASDAQ OMX common stock over a trading period prior to the closing. Based on the NASDAQ OMX stock price on the date of the agreement, NASDAQ OMX currently expects to issue approximately one million shares annually over 15 years. The contingent future issuances of NASDAQ OMX common stock are subject to anti-dilution protections and acceleration upon certain events. NASDAQ OMX expects to finance the cash portion of the purchase price through the use of cash on hand, the incurrence of indebtedness, which may include senior notes, and/or the issuance of securities. The transaction is subject to customary regulatory approvals and is expected to close in the second half of 2013. Upon closing, this business will be integrated into our Market Services and Information Services segments which will diversify these businesses and allow us to maximize new opportunities in the trading of fixed income securities around the globe.

17. Subsequent Events

2013 Acquisition

Dutch Cash Equities and Equity Derivatives Trading Venue

In April 2013, we acquired a 25% equity interest in TOM. The terms of the transaction also provide us an option to acquire an additional 25.1% of the remaining shares at a future date. This transaction delivers on our strategy to expand our derivatives presence across the European market and is part of our Market Services segment. We will account for our investment in TOM under the equity method of accounting.

2013 Proposed Acquisition

Agreement to acquire eSpeed for Trading of U.S. Treasuries

In April 2013, we announced an agreement with BGC to acquire eSpeed.

Under the terms of the agreement, the purchase price will consist of $750 million in cash, subject to adjustment for certain pre-paid amounts and accrued costs and expenses, and contingent future issuances of NASDAQ OMX common stock approximating certain tax benefits associated with the transaction. Such contingent future issuances of NASDAQ OMX common stock will be paid ratably over 15 years if NASDAQ OMX achieves a designated revenue target in each such year, with such common stock valued based on the volume-weighted average price of NASDAQ OMX common stock over a trading period prior to the closing. Based on the NASDAQ OMX stock price on the date of the agreement, NASDAQ OMX currently expects to issue approximately one million shares annually over 15 years. The contingent future issuances of NASDAQ OMX common stock are subject to anti-dilution protections and acceleration upon certain events.

NASDAQ OMX expects to finance the cash portion of the purchase price through the use of cash on hand, the incurrence of indebtedness, which may include senior notes, and/or the issuance of securities. The transaction is subject to customary regulatory approvals and is expected to close in the second half of 2013. Upon closing, this business will be integrated into our Market Services and Information Services segments which will diversify these businesses and allow us to maximize new opportunities in the trading of fixed income securities around the globe.