Condensed Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 131,905	$ 135,298	$ 430,418	$ 390,268
Other comprehensive income (loss):
Foreign currency translation adjustment, before reclassification and tax:	(7,161)	(15,081)	(11,838)	(8,982)
Less: reclassification adjustment for gains included in net income upon liquidation	0	0	1,542	0
Foreign currency translation adjustments, before tax	(7,161)	(15,081)	(13,380)	(8,982)
Income tax expense	0	0	0	0
Foreign currency translation adjustments, net of tax	(7,161)	(15,081)	(13,380)	(8,982)
Unrealized (losses) gains on investments:
Unrealized (losses) gains arising during period	(11)	(36)	(352)	806
Less: reclassification adjustment for gains included in net income	1,270	5	1,270	2
Change in unrealized (losses) gains on investments	(1,281)	(41)	(1,622)	804
Income tax benefit (expense)	420	126	700	(160)
Unrealized (losses) gains on investments, net of tax	(861)	85	(922)	644
Changes in employee benefit related items:
Amortization of prior service cost	0	(1,299)	0	(3,898)
Recognized actuarial gain	251	487	726	1,461
Changes in employee benefit related items	251	(812)	726	(2,437)
Income tax (expense) benefit	(22)	18	(87)	8
Employee benefit related items, net of tax	229	(794)	639	(2,429)
Other comprehensive (loss)	(7,793)	(15,790)	(13,663)	(10,767)
Less: Comprehensive (loss) income in consolidated entities attributable to non-controlling interests	(3,109)	(4,583)	4,782	(2,740)
Comprehensive income attributable to AB Unitholders	$ 127,221	$ 124,091	$ 411,973	$ 382,241