WASHINGTON, Nov 16 (Reuters) - U.S. Treasury Secretary Janet Yellen on Tuesday extended a deadline for a potential U.S. government payment default to Dec. 15 from Dec. 3, giving Congress more time to raise the federal debt ceiling after considering a massive social spending bill. Yellen said in a letter to congressional leaders that she has a high degree of confidence that Treasury will be able to finance the government through Dec. 15 and make a $118 billion transfer to the Highway Trust Fund required on that date. But beyond Dec. 15, Treasury would be left with “insufficient remaining resources” without a debt limit increase. (Reporting by David Lawder and Andrea Shalal, Editing by Rosalba O’Brien)