Republicans will retain their Senate majority as GOP incumbents hang onto key seats in Wisconsin, Pennsylvania, North Carolina, Indiana and Florida.
Four states remain to be decided. In Alaska, Republican Sen. Lisa Murkowski is favored to win a new term, while races in Missouri and New Hampshire were too close to call early Wednesday. A race in Louisiana is headed for a runoff next month, where the Republican is favored.
Republicans were defending a slim 54-46 majority.
Democrats grabbed a Republican-held seat in Illinois, but the outcome in Wisconsin was a surprise as both parties had expected it to flip for the Democrats.