Wouldn't you consider Bretton Woods killed by Nixon taking the USA off the gold standard. That ended the gold link. I think the floating started shortly there after.
BUMP!
But the fact that Eurodollars were preferred method of settling accounts also had an effect. European banks had large holdings of US dollars which made it much easier for Nixon to take the US off the gold standard. He also convinced the Saudis to price oil in US dollars, stimulating more demand for Eurodollars.
In an immediate sense, but why did he do that? Because the currency had been debased when LBJ wanted to spend a lot of money on Vietnam and the Great Society without passing the burden on to current taxpayers. (The prevailing gold standard obviously failed to prevent this.) The Fed accommodated him, and the old gold-$ rate was simply unsustainable.