The Congressional Budget Office (CBO) released a report Tuesday detailing the costs and objectives associated with upgrading America’s nuclear weapons arsenal.

The report, titled ‘Projected Costs of U.S. Nuclear Forces, 2017 to 2026’ outlines the programs slotted for upgrades. CBO estimates that the effort will cost $400 billion, an increase over the $348 billion estimate released in 2015.

To address the issue of nuclear modernization, in 2013 Congress directed the CBO to produce 10-year cost projections to operate, maintain, and update America’s nuclear weapons, and report on those costs every two years. CBO says the over $60 billion increase from 2015 to now reflects the additional two-year period not covered in the last report.

The U.S. has three methods of delivering a nuclear weapon on target: Intercontinental Ballistic Missiles (ICBMs), submarine launched ballistic missiles (SSBNs), and long-range bombers like the B-52. All of the current programs are Cold War technology, upgraded over the last few decades simply to keep them operational.

The Minuteman III missile, in service since 1970, is scheduled to be replaced during this 10-year time period through a program called Ground-Based Strategic Deterrent. A new ICBM will be developed and fielded. Three new submarines will be authorized and under construction by 2026. The replacement for the B-52 will be the B-21, expected to be in service by 2025.

While the threat of nuclear annihilation has seemingly dimmed since the fall of the Soviet Union, the U.S. has 1,361 deployed nuclear weapons compared to Russia’s 1,796 (which doesn’t include the thousands each country has in storage); enough to completely destroy both countries and likely have a catastrophic effect on the global climate.

Both the U.S. and Russia have agreed to further reductions in the number of nuclear warheads as per the provisions of the 2011 New START (Strategic Arms Reduction Treaty).

However, studies have shown that even a ‘small’ nuclear exchange, for example one between India and Pakistan, could have global ramifications.