Actually I'd skip the aux cable and go with an Anker Soundsync Drive bluetooth to aux adapter. https://www.anker.com/products/variant/SoundSync-Drive/A3351011
It works really well, and it has a mic so you don't have to worry about google now/other voice inputs not enjoying being plugged into an aux with no mic. Plus you don't have to plug anything into your phone to listen to music, or take a call.
Add a 2 port usb car charger to power it, and charge your phone and you are golden, that was my setup in my old Toyota for 2 solid weeks it worked great, right before my car got stolen. (Thankfully my power drive speed adapter hadn't come yet or I'd have been really mad)