Investments - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended				12 Months Ended
	Dec. 29, 2015	Dec. 31, 2015	Sep. 30, 2015	Sep. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Proceeds from sale of cost method investment		$ 3,500
Receivables from sale of investment		$ 2,517,735				$ 2,517,735	$ 2,712,820
Proceeds and distributions from investments						34,620	58,660	$ 3,251
Investment income and other, net						$ 421,384	41,232	$ 124,095
BATS
Schedule of Equity Method Investments [Line Items]
Percentage of equity in common stock of private companies cover under strategic investment		16.70%				16.70%
Percentage of voting interest held		19.90%				19.90%
BATS and DE
Schedule of Equity Method Investments [Line Items]
Proceeds and distributions from investments					$ 42,200
Merger related transaction costs					6,600
DE
Schedule of Equity Method Investments [Line Items]
Investment income and other, net					16,200
TM Holdings
Schedule of Equity Method Investments [Line Items]
Investment income and other, net				$ 17,600
Financial instruments owned, at fair value
Schedule of Equity Method Investments [Line Items]
Investments reclassified to trading security, fair value			$ 2,800
Other assets
Schedule of Equity Method Investments [Line Items]
Receivables from sale of investment		$ 5,800				$ 5,800
Investment income and other, net
Schedule of Equity Method Investments [Line Items]
Income from equity method investments						21,000	36,000
Gain from reclassification of investments to trading security						500
Realized gain from sale of cost method investment						9,300
Investment income and other, net | Aperture
Schedule of Equity Method Investments [Line Items]
Gain from sale of investment	$ 10,500					$ 10,500
Investment income and other, net | BATS and DE
Schedule of Equity Method Investments [Line Items]
Investment income and other, net					$ 9,600
Investment income and other, net | tradeMONSTER
Schedule of Equity Method Investments [Line Items]
Investment income and other, net				$ 15,100			$ 15,100