The Federal Communications Commission, doubling its investment in high-speed Internet at schools, on Monday pledged an additional $2 billion over two years for improving broadband networks in schools and libraries. The investment comes through E-Rate, a subsidy program funded by fees Americans pay on their monthly phone bills that helps schools and libraries get discounts on Internet services and digital devices. But demand has far exceeded that amount, FCC officials have said, and of all E-Rate funding, only about half has gone toward equipping schools and libraries with true high-speed Internet access, the agency said. In what FCC Chairman Tom Wheeler called a business-like approach, the agency would reshuffle how it spends the current E-Rate funds to prioritize high-capacity Internet connections over other purposes and to improve the programs efficiency and management.