Of course, confirm everything with your bank. There may be exceptions, get the sure answer from them.

FDIC - US Banks' Checking and Savings Account Insurance

Deposits (in any currency) are covered at member banks with the same coverage level as American resident-citizens for those that aren't resident and/or citizens. But ONLY through US Branches is there coverage. So, there will not be FDIC coverage on a bank's subsidiary that is based outside of the US, such as those international banking divisions based on little islands/countries that don't have as strong banking regulations.

FDIC Deposits in Foreign Currencies

So, these are covered, from the FDIC's Guide to Deposit Insurance:

(12 C.F.R. § 330.3(c) (this section of the law has all of the answers, it's a "General Principle" of the FDIC)

"Deposit insurance coverage is provided for deposits in an insured bank that are denominated in a foreign currency. Deposit insurance for such deposits will be determined in the amount of United States dollars that is equivalent in value to the amount of the deposit denominated in the foreign currency. If an insured bank fails, the value of the deposit will be determined using the rate of exchange "noon rates" for United States dollars as of the date the bank is closed. "

CDIC: Canadian Deposit Insurance Corporation (for CDN banks)

The answer seems to be yes, your CDIC deposits are covered in the same way that they are covered as if you were a Canadian Citizen or Resident. So, Americans or Brits with Canadian Bank accounts will have the same protections. The Canadian Citizens won't be first in line with you being 2nd in line if the bank goes under or anything. The only exception I can think of that might be relevant is that the CDIC only covers deposits in Canadian Dollars. So, if you have a EURO, US$ or Peso account or anything else, it would _NOT_ be covered in the event of a bank failure. A US$ account at a Canadian bank is _not_ insured, and for this, you might want to consider opening up a US Bank account in the USA, which would be eligible for FDIC insurance as above, including non-US$ deposits.

Canadian credit unions have their own insurance, usually through provincial-wide deposit insurance corporations, which are not officially, but assumed to be back by their provincial governments. (In other words, people think that the provinces will bail them out if the deposit insurance corporation fails, which remains to be seen, one has yet to even teeter on failing).

How able are the CDIC and FDIC able to pay if a bank fails?

Well, that's a much harder question to answer. As far as I know, the FDIC has rather substantial reserves in the tens of billions. But a series of bank failures would raise an interesting question, as the FDIC would need to be bailed out by the federal government. I believe this bailout is not automatic, but hopefully would happen (if ruling party ever wants to win an election ever again).