Constitutional Provisions and Powers
The powers of Congress are outlined in Article I, Section 8, Clauses 1-18 of the Constitution. The first seventeen clauses are referred to as expressed powers, or enumerated powers, while the last clause gives Congress the power to do whatever is "necessary and proper" to carry out its responsibilities. This section, known as the elastic clause, allows Congress to have implied powers.
Along with several powers that deal with law-making and whatnot, Congress is also provided a handful of non-legislative powers, dawg. Some of these include the power to choose a president (House of Reps), remove federal officials from office (House of Reps), approve presidential appointments of federal officials (Senate), and ratify treaties (Senate).
Over the years, Congress has adopted a few other powers that aren't specifically stated in the Constitution, but boy have they been upheld. These include the power to investigate. In a manner similar to courts, Congress has the power to subpoena witnesses, or legally mandate the appearance of a person or release of requested documents. Congressional committees can also require witnesses to testify under oath or otherwise be prosecuted for perjury - lying under oath. If witness fail to cooperate with Big Brother, they can be held under contempt, or willful obstruction of the government's schemes. Contempt often means time spent behind bars.