A year ago, the U.S. Navy ordered the first two DDG 1000 destroyers. This is the "Zumwalt" class, and each of the first two was to cost $3.3 billion. At that point, the navy was only planning to buy seven Zumwalts. Since then, the buy has been reduced to three ships, and the cost (partly because R&D had to be spread over fewer ships) escalated to $6 billion a ship. That's about what a 100,000 ton Nimitz class aircraft carrier costs.
Cutting the buy to seven ships, and then to three, was partly due to the escalating cost of the ships, and partly because the Zumwalts were seen as the wrong ship, at the wrong time. For one thing, the navy was eager to build more of the older, and cheaper, DDG 51s, which had proven highly capable, especially when they underwent an inexpensive modification that gave them the ability to shoot down ballistic missiles. There is now talk of tweaking the DDG 51 design a bit, and forgetting all about DDG 1000.
Compared to the previous class of American destroyers (the DDG 51s), the Zumwalts are very different. The DDG 51s displaced 9,200 tons and had a crew of 360 sailors. The DDG 1000s displace 14,000 tons and have a crew of 142. The DDG 1000s are stealthy and carry a larger gun (two automated, long range 155mm weapons). It also has 80 vertical cells for anti-aircraft, land attack and anti-ship missiles. It can carry one or two helicopters, plus three RQ-8A helicopter UAVs. The DDG 1000s are highly automated and are crammed with the latest electronics. After the first two are built, the next five are expected to cost about $2 billion each. The first DDG 1000 will enter service in 4-5 years.