Income Taxes (Details)	9 Months Ended
Sep. 30, 2012
Income Taxes [Abstract]
New York City unincorporated business tax rate (in hundredths)	4.00%

Tax rate attributable to operating income for unincorporated business entities operating in New York City, before credits paid for unincorporated business entities by a subsidiary.

No definition available.

Name:	ablp_NewYorkCityUnincorporatedBusinessTaxRate
Namespace Prefix:	ablp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration