3.25.0.1 html 373 36 1 false 93 0 false 6 false false R1.htm 030000 - Disclosure - Form N-CSR Cover Sheet http://xbrl.sec.gov/oef/role/NcsrCover Form N-CSR Cover Cover 1 false false R2.htm 030001 - Disclosure - Shareholder Report Sheet http://xbrl.sec.gov/oef/role/ShareholderReport Shareholder Report Notes 2 false false R3.htm 040010 - Disclosure - Shareholder Report, Line Graph (Details) Sheet http://xbrl.sec.gov/oef/role/ShareholderReportLineGraphDetails Shareholder Report, Line Graph (Details) Details 3 false false R4.htm 040015 - Disclosure - Shareholder Report, Average Annual Return (Details) Sheet http://xbrl.sec.gov/oef/role/ShareholderReportAverageAnnualReturnDetails Shareholder Report, Average Annual Return (Details) Details 4 false false R5.htm 040020 - Disclosure - Shareholder Report, Holdings (Details) Sheet http://xbrl.sec.gov/oef/role/ShareholderReportHoldingsDetails Shareholder Report, Holdings (Details) Details 5 false false All Reports Book All Reports bw-20241231.xsd d788087dncsrs.htm g788087i09029d4d849e329e1b27.jpg g788087i0dc1a7817a280cb80467.jpg g788087i0fbad093a4d5eb6ec71d.jpg g788087i1650e197545c3bf76701.jpg g788087i1a0e7dbbb76549c6fe0e.jpg g788087i328dab4f106cbef79c96.jpg g788087i3a5d53f2f56204401a9a.jpg g788087i486fa976d2deb922aaf9.jpg g788087i488f23bc5e1893721b8b.jpg g788087i4c9cd9bee42401c7bdc4.jpg g788087i574d82853b0576668b4e.jpg g788087i5d938d4fb3ff1a4c35af.jpg g788087i5e5774f0f114bf20c3a5.jpg g788087i5f8b7445cc15e43fe1e4.jpg g788087i5fa3e41437f566101956.jpg g788087i7293727e37552471b48f.jpg g788087i7908b8936e5716dadcb9.jpg g788087i85feef4ab9117eb108b0.jpg g788087i95669daa0a83e7e012ab.jpg g788087i9be503d79d5881171ee3.jpg g788087ibea745bd14d1e234aa02.jpg g788087iee166d062f99e95075c9.jpg g788087if98aeec9b2419ba42b24.jpg g788087ifa7788bbbd175da0d198.jpg g788087iff79bf1e096c68ba1016.jpg g788087logo.jpg g788087page1.jpg http://fasb.org/us-gaap/2024 http://xbrl.sec.gov/dei/2024 http://xbrl.sec.gov/oef/2024 false false