I've put ATF in my dad's Rolls power steering and in my boat's power steering but those are GM cars. This was actually recommended by a mechanic for in case of emergency it would work fine.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.