In the BT era (before Trump) the cable news channels did okay, with Fox News almost always a top 5 cable channel. Back then, CNN and MSNBC were usually found in the upper teens or twenties. But with non-stop news from Washington, all three channels have consistently been in the top 10.
For Q3 2017, Fox News was the No. 1 cable network in both prime time and total day. MSNBC was No. 2 in prime time and No. 3 in total day. CNN was No. 8 in prime time and No. 6 in total day:
For last week, in total day viewing, Fox News was No. 1, MSNBC was No. 4, and CNN was No. 7. In prime time, ESPN, with the return of Monday Night Football, was No. 1, followed by FNC at No. 2 and MSNBC at No. 3.