Summary: Here's everything you need to know before Tuesday's opening bell: Comcast Corp. bid nearly $31 Billion for Britain's Sky PLC. . A national security panel is reportedly looking into Broadcom Ltd's plan to take over Qualcomm Inc. . Fitbit Inc. tanked on an earnings miss. Palo Alto Networks jumped premarket after topping its earnings expectations and raising its outlook. U.S. stock futures pointed lower ahead of Jerome Powell's testimony. Watch TheStreet's investing interviews on Youtube
