If you have Qgis, you can ask gdalsrsinfo in the OSGeo4w shell:
gdalsrsinfo "+proj=tmerc +lat_0=0 +lon_0=-114 +k=0.9999 +x_0=0 +y
_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs"
PROJ.4 : '+proj=tmerc +lat_0=0 +lon_0=-114 +k=0.9999 +x_0=0 +y_0=0 +ellps=GRS80
+towgs84=0,0,0,0,0,0,0 +units=m +no_defs '
OGC WKT :
PROJCS["unnamed",
GEOGCS["GRS 1980(IUGG, 1980)",
DATUM["unknown",
SPHEROID["GRS80",6378137,298.257222101],
TOWGS84[0,0,0,0,0,0,0]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433]],
PROJECTION["Transverse_Mercator"],
PARAMETER["latitude_of_origin",0],
PARAMETER["central_meridian",-114],
PARAMETER["scale_factor",0.9999],
PARAMETER["false_easting",0],
PARAMETER["false_northing",0],
UNIT["Meter",1]]
The WKT parameters should be usable with Arcgis.