I wouldn't be so sure that ideology is a huge factor in answering this question. There are some cases, like Tammy Baldwin and Ron Johnson, where it is genuinely difficult to imagine a state's senators giving each other the time of day because they just cut such vastly different figures politically, but there are many high-profile examples of lawmakers who came from different parties or different factions of the same party who were personally close--Ted Kennedy and Orrin Hatch, Al Franken and Jim DeMint, Mark Meadows and Elijah Cummings in the House, Sarah Palin and Mary Peltola on the state level back in Alaska.
Kevin McCarthy spoke at my university in spring 2019 and mentioned that he was really good friends with Joe Kennedy III.
