3.7.0.1 html 380 72 1 true 318 0 false 4 false false R1.htm 010001 - Document - Document And Entity Information {Elements} Sheet http://jhvit-20170501/role/DocumentDocumentandEntityInformation Document And Entity Information 1 false true R2.htm 010002 - Document - John Hancock Variable Insurance Trust {Unlabeled} Sheet http://jhvit-20170501/role/AAAA John Hancock Variable Insurance Trust 2 false false R7.htm 040000 - Disclosure - Risk/Return Detail Data {Elements} Sheet http://xbrl.sec.gov/rr/role/RiskReturnDetailData Risk/Return Detail Data 3 false false All Reports Book All Reports jhvit-20170501.xml jhvit-20170501.xsd jhvit-20170501_def.xml jhvit-20170501_lab.xml jhvit-20170501_pre.xml BarChart1.png BarChart2.png BarChart3.png BarChart4.png BarChart5.png BarChart6.png BarChart7.png BarChart8.png BarChart9.png BarChart10.png BarChart11.png BarChart12.png BarChart13.png BarChart14.png BarChart15.png BarChart16.png BarChart17.png BarChart18.png BarChart19.png BarChart20.png BarChart21.png BarChart22.png BarChart23.png BarChart24.png BarChart25.png BarChart26.png BarChart27.png BarChart28.png BarChart29.png BarChart30.png BarChart31.png BarChart32.png BarChart33.png BarChart34.png BarChart35.png BarChart36.png BarChart37.png BarChart38.png BarChart39.png BarChart40.png BarChart41.png BarChart42.png BarChart43.png BarChart44.png BarChart45.png BarChart46.png BarChart47.png BarChart48.png BarChart49.png BarChart50.png BarChart51.png BarChart52.png BarChart53.png BarChart54.png BarChart55.png BarChart56.png BarChart57.png BarChart58.png BarChart59.png BarChart60.png BarChart61.png BarChart62.png true false