[yummyfajitas]

1) Countrywide was a bank, later a thrift, which providing financial services (mortgages, insurance) to retail customers. That's pretty much the definition of a retail bank.

2) AIG was not doing anything that Glass-Steagall would prevent. The fact that your 20/20 hindsight says it created a systematic risk doesn't change this.

3) Citi received $20B in TARP money, and paid it back quite rapidly. It's unknown how much in needed - many banks were forced to take unnecessary money in order to prevent identification of which banks were in trouble.

Also, why do you believe that preventing Citi from mixing retail and investment banking together would have prevented the (hypothetical multiple pieces of) city from requiring $20B?