The Economist reports that "despite falling spending, America’s military pre-eminence is vast. A budget of $600 billion for 2014, including $84 billion for 'overseas contingency operations' such as Afghanistan, buys a weighty punch. Next year, when the Pentagon’s base budget is expected to fall to $498 billion (spending in Afghanistan is uncertain, but will be much lower), America’s military outlays will still be around 35% of the global total. Its main allies account for another 25% or so. China and Russia combined spend less than half what America does, though their costs are lower."
However, the piece continues: "the Pentagon is getting less bang for its buck. Personnel costs rose by 59% after inflation between 2001 and 2012, despite a mere 3% increase in the number of people employed. 'Operational and maintenance' costs increased by 34% in real terms. Congress hates curbing military pay or closing unwanted bases, two things the Pentagon says are needed if enough money is to be spent on new weapons. The yawning gap between Uncle Sam and his potential foes seems bound to shrink."