White House chief strategist Steve Bannon disclosed at least $1.3 million in income last year, largely from a consulting firm and entities backed by the billionaire Mercer family, according to financial disclosures released late Friday.

Bannon, who helped to bring a fiery economic populism to President Donald Trump's White House, reported as much as $2.3 million in income. He also disclosed between $13 million and $56 million in assets.

The report is among the roughly 180 employee financial disclosure documents the White House made available Friday. The legally required documents shed light on the financial holdings of Trump's administration, which features a largely unprecedented amount of wealth and possible ethics pitfalls.

He reported $191,000 in income from Breitbart, about $125,000 from data firm Cambridge Analytica and about $61,000 from the Government Accountability Institute, all of which are backed by the Mercer family. The megadonors supported Ted Cruz in the Republican primary before putting big money behind Trump's general election effort.

Bannon reported nearly $500,000 in income from Bannon Strategic Advisors and disclosed a stake in the company of $5 million to $25 million.

The document said Bannon has an agreement in principle to sell stakes in some entities.

It also says that he stepped down as executive chairman of Breitbart in August.

— CNBC's Christine Wang contributed to this report.