Clinton: Last days at State Dep't 'have been bittersweet'

"Tomorrow is my last day as Secretary of State and though it is hard to predict what any day in this job will bring, I know that tomorrow my heart will be very full," said Clinton during remarks on American Leadership at the Council on Foreign Relations.

The Senate officially approved Sen. John Kerry (D-Mass.) to succeed Clinton in leading the State Department in a near-unanimous vote on Tuesday.

The outgoing secretary, who has logged more miles in her post than anyone to hold the position before her, had high praise for her staff and colleagues.

"Serving with the men and women of the State Department and USAID has been a singular honor and Sec. Kerry will find there is no more extraordinary group of people working anywhere in the world," she said. "So these last days have been bittersweet for me, but this opportunity that I have here before you gives me some time to reflect on the distance that we've traveled and take stock on what was done and what is left to do."

During her final public speech as a member of President Obama's Cabinet, Clinton refuted those that believe the United States is in decline, and called for continued American leadership around the world.

"When I say we are truly the indispensable nation it's not meant as a boast or an empty slogan. It's a recognition of our role and our responsibilities. That's why all the declinists are dead wrong. It's why the United States must and will continue to lead in this century, even as we lead in new ways," Clinton said.

She also used to opportunity to address the Sept. 11 attack in Benghazi, Libya, that led to the death of U.S. Ambassador Christopher Stevens and three other Americans, an event that has left an indelible mark on the secretary's tenure.

"And we know, leadership has its costs. We know it comes with risks and can require great sacrifice. We've seen that painfully again in recent months, but leadership is also an honor. One that Chris Stevens and his colleagues in Benghazi embodied and we must always strive to be worthy of that honor," Clinton said.