Today, the IRS provided the full details of the tax payment extension in Notice 2020-17.
The notice provides that individuals may defer up to $1 million of Federal income tax payments ($10 million for corporations) until July 15, 2020. For this purpose, Federal income tax payments include the final payment for the 2019 tax year AND any quarterly estimated tax payment due on April 15, in the aggregate. Taxpayers do not get a separate deferral amount for each tax year.
The tax payment deferral only applies to Federal income tax payments and for now, the due date for Federal tax returns are not delayed.
If you have any questions, please reach out to your advisor.