Investment in AllianceBernstein (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Investment in AllianceBernstein [Abstract]
Investment in AllianceBernstein, beginning of period	$ 1,533,654
Equity in net income attributable to AllianceBernstein Unitholders	41,371	42,997
Changes in accumulated other comprehensive income (loss)	537	(3,719)
Additional investments in AllianceBernstein from cash distributions paid to AllianceBernstein consolidated rabbi trust	26	5,929
Additional investments with proceeds from exercises of compensatory options to buy Holding Units, net	4,656	6,642
Cash distributions received from AllianceBernstein	(63,457)	(40,077)
Capital contributions to AllianceBernstein	5,772	0
AllianceBernstein Holding Units retired	(1,606)
AllianceBernstein Holding Units issued to fund long-term incentive compensation plans	210
Change in Holding Units held by AllianceBernstein for long-term incentive compensation plans	1,468
Investment in AllianceBernstein, end of period	$ 1,522,631