Paul Giamatti and Maggie Siff, paying the estranged power couple Chuck and Wendy Rhoades, have been excellent on this series, and especially coiled and intense this season, as they circle each other as well as outsiders. But their intensity is, if anything, outshone this year by Damian Lewis as billionaire Bobby Axelrod, who’s fighting hard to retain and expand his power base. With so many billionaires in and around the White House, his performance in Billions has even more resonance – and relevance.