US Taxes on Foreign Pension Income

My wife is dual citizen of the US and Colombia. She just received a pension bonus of about $25,000 covering the work she did in Colombia for various employers. She has been living the US for over 20 years. Is my understanding correct that we are potentially liable to pay US Taxes on this pension bonus, but that it would be offset by the taxes she pays in Colombia? When do we need to pay the US taxes on this pension bonus, the year she actually received it or the year she pays taxes to Colombia so we can see what US taxes we need to pay?