Read Dean Baker' analysis here.
An excerpt: "Unlike the debt held by Social Security, the debt held by the Fed is not tied to any specific obligations. The bonds held by the Fed are assets of the Fed. It has no obligations that it must use these assets to meet. There is no one who loses their retirement income if the Fed doesn’t have its bonds. In fact, there is no direct loss of income to anyone associated with the Fed’s destruction of its bonds. This means that if Congress told the Fed to burn the bonds, it would in effect just be destroying a liability that the government had to itself, but it would still reduce the debt subject to the debt ceiling by $1.6 trillion. This would buy the country considerable breathing room before the debt ceiling had to be raised again. President Obama and the Republican congressional leadership could have close to two years to talk about potential spending cuts or tax increases. Maybe they could even talk a little about jobs".