Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 592,977	$ 570,839	$ 527,422
Other comprehensive (loss) income:
Foreign currency translation adjustments, before reclassification and tax:	(15,396)	(20,872)	(12,422)
Less: reclassification adjustment for gains included in net income upon liquidation	1,542	0	0
Foreign currency translation adjustments, before tax	(16,938)	(20,872)	(12,422)
Income tax benefit	0	0	0
Foreign currency translation adjustments, net of tax	(16,938)	(20,872)	(12,422)
Unrealized (losses) gains on investments:
Unrealized (losses) gains arising during period	(357)	1,649	819
Less: reclassification adjustment for gains included in net income	1,256	19	4,715
Changes in unrealized (losses) gains on investments	(1,613)	1,630	(3,896)
Income tax benefit (expense)	701	(766)	1,130
Unrealized (losses) gains on investments, net of tax	(912)	864	(2,766)
Changes in employee benefit related items:
Amortization of transition asset	0	0	(47)
Amortization of prior service cost	895	5,197	(5,828)
Recognized actuarial gain (loss)	3,267	(19,656)	22,853
Changes in employee benefit related items	2,372	(24,853)	28,634
Income tax (expense) benefit	(165)	298	(444)
Employee benefit related items, net of tax	2,207	(24,555)	28,190
Other comprehensive (loss) income	(15,643)	(44,563)	13,002
Less: Comprehensive income in consolidated entities attributable to non-controlling interests	6,242	355	9,603
Comprehensive income attributable to AB Unitholders	$ 571,092	$ 525,921	$ 530,821