Changes in Capital (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Changes in capital [Roll Forward]
Beginning balance			$ 4,085,465
Beginning balance			30,396
Beginning balance			4,115,861
Comprehensive income [Abstract]
Net income	$ 155,769	$ 136,432	298,513	$ 254,970
Other comprehensive income, net of tax [Abstract]
Foreign currency translation adjustments	6,056	3,950	(6,219)	6,099
Changes in employee benefit related items	235	(802)	410	(1,635)
Comprehensive income attributable to AB Unitholders	155,008	139,862	284,752	258,151
Distributions to General Partner and unitholders			(313,597)	(298,022)
Purchases of AB Units			(726)	(1,020)
Ending balance	4,055,640		4,055,640
Ending balance	38,717		38,717
Ending balance	4,094,357		4,094,357
Partners' Capital Attributable to AB Unitholders [Member]
Changes in capital [Roll Forward]
Beginning balance			4,085,465	4,027,486
Comprehensive income [Abstract]
Net income			290,563	253,160
Other comprehensive income, net of tax [Abstract]
Unrealized gains on investments			(61)	559
Foreign currency translation adjustments			(6,160)	6,067
Changes in employee benefit related items			410	(1,635)
Comprehensive income attributable to AB Unitholders			284,752	258,151
Distributions to General Partner and unitholders			(313,597)	(298,022)
Distributions from non-controlling interests			0
Distributions to non-controlling interests				0
Purchases of AB Units				(1,020)
Compensation-related transactions			(1,047)	21,160
Other			67
Ending balance	4,055,640	4,007,755	4,055,640	4,007,755
Non-Controlling Interests in Consolidated Entities [Member]
Changes in capital [Roll Forward]
Beginning balance			30,396	42,240
Comprehensive income [Abstract]
Net income			7,950	1,810
Other comprehensive income, net of tax [Abstract]
Unrealized gains on investments			0	0
Foreign currency translation adjustments			(59)	32
Changes in employee benefit related items			0	0
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest			7,891	1,842
Distributions to General Partner and unitholders			0	0
Distributions from non-controlling interests			430
Distributions to non-controlling interests				(11,375)
Purchases of AB Units				0
Compensation-related transactions			0	0
Other			0
Ending balance	38,717	32,707	38,717	32,707
Total Capital [Member]
Changes in capital [Roll Forward]
Beginning balance			4,115,861	4,069,726
Comprehensive income [Abstract]
Net income			298,513	254,970
Other comprehensive income, net of tax [Abstract]
Unrealized gains on investments			(61)	559
Foreign currency translation adjustments			(6,219)	6,099
Changes in employee benefit related items			410	(1,635)
Comprehensive income			292,643	259,993
Distributions to General Partner and unitholders			(313,597)	(298,022)
Distributions from non-controlling interests			430
Distributions to non-controlling interests				(11,375)
Purchases of AB Units				(1,020)
Compensation-related transactions			(1,047)	21,160
Other			67
Ending balance	$ 4,094,357	$ 4,040,462	$ 4,094,357	$ 4,040,462