db={"Members":[{"_id":ObjectId("53ad60c1600f5b241c693cbd"),"items":[{"Type":["Medicaid ID","Medicare ID","Amisys ID","Social Security Number","Market Prominence ID","MBI","MPI"],"Value":["221075***","450807099M","C0004125301","45*******","N00020269104","3K13EA8EY99","17296217"]}]}]}

db.Members.aggregate([{$unwind:"$items"},{$project:{_id:1,data:{$map:{input:{$range:[0,{$size:"$items.Type"},1]},in:{k:{$arrayElemAt:["$items.Type","$$this"]},v:{$arrayElemAt:["$items.Value","$$this"]}}}}}},{$replaceRoot:{newRoot:{$arrayToObject:{$concatArrays:[[{k:"_id",v:"$_id"}],"$data"]}}}}])