Congressional Republicans conceded defeat on Wednesday in their bitter budget fight with President Obama over the new health care law as the House and Senate approved last-minute legislation ending a disruptive 16-day government shutdown and extending federal borrowing power to avert a financial default with potentially worldwide economic repercussions. With the Treasury Department warning that it could run out of money to pay national obligations within a day, the Senate voted overwhelmingly on Wednesday evening, 81 to 18, to approve a proposal hammered out by the chamber's Republican and Democratic leaders after the House on Tuesday was unable to move forward with any resolution.