“Now what information about my oversea accounts do I have to provide?”-->It depends on your status. Are you a US citizen or a US resident for tax purposes??? If yes, then you are liable for US taxes, both federal and state taxes( actually 9 states do NOT impose taxes on their residents in US) on your European income an US source income( if you have in US). As a US person, you can claim your foreign taxes that you paid to foreign taxing authorities on your foreign income on your US federal return but NOT on your state return. ON the contrary, as a non US person, in general, you are liable for taxes only on your US source income; you do NOT have to report your income in Europe to the US IRS, OK???
“ Just earnings? Everything including bank statement? Nothing at all?”----> As a US citizen or as a US resident under either US Tax Law od US INS rules, you ,when you have at any time during a calendar year more than $10,000 in one or more foreign bank and financial accounts; that means all foreign accounts are combined on any day during the year to determine if the over $10,000 figure is reached, MUST file the TDF 90-22.1 form with the IRS by June 30th following the end of the calendar year it is reporting. In 2004 the law changed when Congress enacted a $10,000 penalty for “without regard for willfulness” for failing to file the form by the June 30th deadline or not filing it for any year when it was required. There are also even greater monetary penalties and criminal penalties ( jail time) for failing to file the form that the IRS may impose on anyone they catch that has not filed or filed the form late. As long as you are a non-US person, a non-resident alien, then you do NOT have to report your foreign bank account to the US IRS.
Please visit the IRS Website here; Report of Foreign Bank and Financial Accounts (FBAR)