Investments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Consolidated Blackstone Funds	Dec. 31, 2013 Consolidated Blackstone Funds
Investment [Line Items]
Investments					$ 671.9	$ 487.8
Recognized net gains related to equity method investments	$ 97.1	$ 71.3	$ 330.1	$ 282.6

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

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