The self-described world's largest renewables developer, SunEdison had amassed huge debts after a two-year buying spree of wind and solar.
"Our decision to initiate a court-supervised restructuring was a difficult but important step to address our immediate liquidity issues," said CEO Ahmad Chatila.
US-based SunEdison has secured $300 million in capital from lien credit holders to keep operating while restructuring.
In the filing, SunEdison listed $20.7 billion in assets and $16.1 billion in liabilities as of 30 September, including its two yieldcos – Terraform Power and Terraform Global – which did not declare bankruptcy.
SunEdison said it expects to sell "non-core" assets.
In 2014, it bought US developer First Wind for $2.4 billion and 930MW of Invenergy wind projects for $2 billion.
The firm also entered a joint venture with Gamesa to develop up to 1GW, focusing on India and Mexico, as well as expanding in solar.
The US Justice Department is investigating the company's accounting practices.