Shareholder Report, Holdings (Details)	Jun. 30, 2026
C000005448 \| Top10HoldingEli LillyBNY-532457108
Holdings [Line Items]
Percent of Net Asset Value	14.10%
C000005448 \| Top10HoldingJohnson & JohnsonBNY-478160104
Holdings [Line Items]
Percent of Net Asset Value	6.60%
C000005448 \| Top10HoldingUnitedHealth GroupBNY-91324P102
Holdings [Line Items]
Percent of Net Asset Value	5.90%
C000005448 \| Top10HoldingAbbVieBNY-00287Y109
Holdings [Line Items]
Percent of Net Asset Value	5.10%
C000005448 \| Top10HoldingMerckBNY-58933Y105
Holdings [Line Items]
Percent of Net Asset Value	4.00%
C000005448 \| Top10HoldingGilead SciencesBNY-375558103
Holdings [Line Items]
Percent of Net Asset Value	2.80%
C000005448 \| Top10HoldingThermo Fisher ScientificBNY-883556102
Holdings [Line Items]
Percent of Net Asset Value	2.50%
C000005448 \| Top10HoldingVertex PharmaceuticalsBNY-92532F100
Holdings [Line Items]
Percent of Net Asset Value	2.30%
C000005448 \| Top10HoldingBristol-Myers SquibbBNY-110122108
Holdings [Line Items]
Percent of Net Asset Value	2.10%
C000005448 \| Top10HoldingAbbott LaboratoriesBNY-002824100
Holdings [Line Items]
Percent of Net Asset Value	1.90%
C000005448 \| Major Pharmaceuticals
Holdings [Line Items]
Percent of Net Asset Value	31.50%
C000005448 \| Other Biotechnology
Holdings [Line Items]
Percent of Net Asset Value	25.70%
C000005448 \| Major Biotechnology
Holdings [Line Items]
Percent of Net Asset Value	10.90%
C000005448 \| Payors
Holdings [Line Items]
Percent of Net Asset Value	8.60%
C000005448 \| Life Sciences
Holdings [Line Items]
Percent of Net Asset Value	7.60%
C000005448 \| Implants
Holdings [Line Items]
Percent of Net Asset Value	7.40%
C000005448 \| Distribution
Holdings [Line Items]
Percent of Net Asset Value	2.10%
C000005448 \| Providers
Holdings [Line Items]
Percent of Net Asset Value	1.90%
C000005448 \| Other Services
Holdings [Line Items]
Percent of Net Asset Value	1.50%
C000005448 \| Investment TypeOther Holdings Grouping
Holdings [Line Items]
Percent of Net Asset Value	2.80%
C000005449 \| Top10HoldingEli LillyBNY-532457108
Holdings [Line Items]
Percent of Net Asset Value	14.10%
C000005449 \| Top10HoldingJohnson & JohnsonBNY-478160104
Holdings [Line Items]
Percent of Net Asset Value	6.60%
C000005449 \| Top10HoldingUnitedHealth GroupBNY-91324P102
Holdings [Line Items]
Percent of Net Asset Value	5.90%
C000005449 \| Top10HoldingAbbVieBNY-00287Y109
Holdings [Line Items]
Percent of Net Asset Value	5.10%
C000005449 \| Top10HoldingMerckBNY-58933Y105
Holdings [Line Items]
Percent of Net Asset Value	4.00%
C000005449 \| Top10HoldingGilead SciencesBNY-375558103
Holdings [Line Items]
Percent of Net Asset Value	2.80%
C000005449 \| Top10HoldingThermo Fisher ScientificBNY-883556102
Holdings [Line Items]
Percent of Net Asset Value	2.50%
C000005449 \| Top10HoldingVertex PharmaceuticalsBNY-92532F100
Holdings [Line Items]
Percent of Net Asset Value	2.30%
C000005449 \| Top10HoldingBristol-Myers SquibbBNY-110122108
Holdings [Line Items]
Percent of Net Asset Value	2.10%
C000005449 \| Top10HoldingAbbott LaboratoriesBNY-002824100
Holdings [Line Items]
Percent of Net Asset Value	1.90%
C000005449 \| Major Pharmaceuticals
Holdings [Line Items]
Percent of Net Asset Value	31.50%
C000005449 \| Other Biotechnology
Holdings [Line Items]
Percent of Net Asset Value	25.70%
C000005449 \| Major Biotechnology
Holdings [Line Items]
Percent of Net Asset Value	10.90%
C000005449 \| Payors
Holdings [Line Items]
Percent of Net Asset Value	8.60%
C000005449 \| Life Sciences
Holdings [Line Items]
Percent of Net Asset Value	7.60%
C000005449 \| Implants
Holdings [Line Items]
Percent of Net Asset Value	7.40%
C000005449 \| Distribution
Holdings [Line Items]
Percent of Net Asset Value	2.10%
C000005449 \| Providers
Holdings [Line Items]
Percent of Net Asset Value	1.90%
C000005449 \| Other Services
Holdings [Line Items]
Percent of Net Asset Value	1.50%
C000005449 \| Investment TypeOther Holdings Grouping
Holdings [Line Items]
Percent of Net Asset Value	2.80%