Changes in Capital (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Changes in capital [Roll Forward]
Partners' capital, beginning balance			$ 4,061,740
Partners' capital attributable to non-controlling interest, beginning balance			1,564
Partner's capital including portion attributable to non-controlling interest, beginning balance			4,063,304
Comprehensive income:
Net income	$ 204,400	$ 157,480	593,172	$ 466,007
Other comprehensive income, net of tax:
Foreign currency translation adjustments	(4,154)	7,735	(14,789)	24,091
Changes in employee benefit related items	286	299	749	755
Other	0	0	374	0
Comprehensive income attributable to AB Unitholders	199,811	148,961	555,898	439,872
Distributions to General Partner and unitholders			(652,991)	(489,049)
Partners' capital, ending balance	3,940,067		3,940,067
Partners' capital attributable to non-controlling interest, ending balance	1,685		1,685
Partner's capital including portion attributable to non-controlling interest, ending balance	3,941,752		3,941,752
Partners’ Capital Attributable to AB Unitholders
Changes in capital [Roll Forward]
Partners' capital, beginning balance			4,061,740	4,032,017
Comprehensive income:
Net income			569,535	415,994
Other comprehensive income, net of tax:
Unrealized gains on investments				9
Foreign currency translation adjustments			(14,760)	23,114
Changes in employee benefit related items			749	755
Other			374
Comprehensive income attributable to AB Unitholders			555,898	439,872
Distributions to General Partner and unitholders			(652,991)	(489,049)
Compensation-related transactions			(58,857)	(89,567)
Capital contributions to affiliates			(1,344)
Capital contributions from affiliates				79
Purchase of non-controlling interest				172
Distributions to non-controlling interests of our consolidated venture capital fund				0
Other			1,044	1,257
Partners' capital, ending balance	3,940,067	3,894,781	3,940,067	3,894,781
Non-Redeemable Non-Controlling Interests In Consolidated Entities
Changes in capital [Roll Forward]
Partners' capital attributable to non-controlling interest, beginning balance			1,564	36,172
Comprehensive income:
Net income attributable to noncontrolling interest			150	9,680
Other comprehensive income, net of tax:
Unrealized gains on investments				0
Foreign currency translation adjustments			(29)	977
Changes in employee benefit related items			0	0
Other			0
Comprehensive income attributable to non-controlling interest			121	10,657
Distributions to General Partner and unitholders			0	0
Compensation-related transactions			0	0
Capital contributions to affiliates			0
Capital contributions from affiliates				0
Purchase of non-controlling interest				(2,005)
Distributions to non-controlling interests of our consolidated venture capital fund				(43,217)
Other			0	0
Partners' capital attributable to non-controlling interest, ending balance	1,685	1,607	1,685	1,607
Total Capital
Changes in capital [Roll Forward]
Partner's capital including portion attributable to non-controlling interest, beginning balance			4,063,304	4,068,189
Comprehensive income:
Net income			569,685	425,674
Other comprehensive income, net of tax:
Unrealized gains on investments				9
Foreign currency translation adjustments			(14,789)	24,091
Changes in employee benefit related items			749	755
Other			374
Comprehensive income			556,019	450,529
Distributions to General Partner and unitholders			(652,991)	(489,049)
Compensation-related transactions			(58,857)	(89,567)
Capital contributions to affiliates			(1,344)
Capital contributions from affiliates				79
Purchase of non-controlling interest				(1,833)
Distributions to non-controlling interests of our consolidated venture capital fund				(43,217)
Other			1,044	1,257
Partner's capital including portion attributable to non-controlling interest, ending balance	3,941,752	$ 3,896,388	3,941,752	$ 3,896,388
Difference between Revenue Guidance in Effect before and after Topic 606 | ASC 606 and ASU 2016-01 | Partners’ Capital Attributable to AB Unitholders
Other comprehensive income, net of tax:
Impact of adoption of revenue recognition standard ASC 606 and ASU 2016-01	34,577		34,577
Difference between Revenue Guidance in Effect before and after Topic 606 | ASC 606 and ASU 2016-01 | Non-Redeemable Non-Controlling Interests In Consolidated Entities
Other comprehensive income, net of tax:
Impact of adoption of revenue recognition standard ASC 606 and ASU 2016-01	0		0
Difference between Revenue Guidance in Effect before and after Topic 606 | ASC 606 and ASU 2016-01 | Total Capital
Other comprehensive income, net of tax:
Impact of adoption of revenue recognition standard ASC 606 and ASU 2016-01	$ 34,577		$ 34,577