COP spun off all refining operations & associated pipelines, their 50% equity investment in CP Chem (their JV with Chevron) and all midstream and associated pipeline operations, including their 50% equity investment in DCP midstream partners (JV with Spectra Energy SE) into a new company Phillips 66 (Ticker PSX). If you owned COP prior to the spin then you received 1 share of PSX for each 2 shares of COP.
If you hold both securities today from the split then you have 1 share of COP worth $60.10 and 1/2 share of PSX worth (1 share PSX of $69.97 divided by 2 = $34.985). Your 1 share of COP back on the day prior to the spin (April 30, 2012 closed at $71.63) is now $95.085 for a gain of $23.455 or 32.74% plus dividends. COP kept the origianal dividend while PSX issued a new dividend and has increased it every quarter since. It appears that it was originally too low and they have tried to move it up. PSX has also paid off significant debt, is buying back stock and is in the process of setting up a MLP in order to drop down certain qualified assets with loew returns, primarily pipeline and rterminals.