Investment in AllianceBernstein (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Investment in AllianceBernstein [Abstract]
Investment in AllianceBernstein, beginning of period			$ 1,560,536
Equity in net income attributable to AllianceBernstein Unitholders	45,440	27,803	88,437	60,510
Changes in accumulated other comprehensive income (loss)	(3,187)	(1,038)	(6,906)	(236)
Additional investments in AllianceBernstein from cash distributions paid to AllianceBernstein consolidated rabbi trust			11,871	3,457
Reclassification of payable to AllianceBernstein	(9,226)		(9,226)
Additional investments with proceeds from exercises of compensatory options to buy Holding Units, net			13,281	0
Cash distributions received from AllianceBernstein			(83,463)	(50,483)
Change in Holding Units held by AllianceBernstein for long-term incentive compensation plans			42,757
Investment in AllianceBernstein, end of period	$ 1,617,287		$ 1,617,287