google map api v3 background color

You can just set backgroundColor: 'none'

var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 11,
    center: {lat: 41.876, lng: -87.624},
    backgroundColor: 'none'
  });

although you removed everything there still be blank tiles present.

You may try to hide those tiles, the following CSS works for me:

  /*the desired background for the map*/
#map_canvas{background-color:#fff !important}

  /*hides the tiles (and maybe more^^)*/
#map_canvas div div div div div div img{visibility:hidden}