American Express Co. (AXP) Tuesday provided some details on its plans to spin off its financial advisers later this year, saying it will inject $1 billion of cash into the unit.

The spinoff is expected to occur in late September, American Express said Tuesday. Shares of the financial advisers unit, which will be called Ameriprise Financial Inc. (search) , will trade on the New York Stock Exchange (search) under the symbol "AMP."

American Express announced the planned spinoff in February. The separation will leave New York-based American Express focused primarily on its core credit-card businesses. The Minneapolis-based financial advisers unit, which will start using the Ameriprise name as of Aug. 1, will offer a wide range of other financial services, including asset and income management, mutual funds, retirement planning and insurance.

The $1 billion cash infusion will cover the expected $875 million pretax costs associated with the spinoff and will allow Ameriprise to become an independent company without needing to raise money from outside sources, said Gary L. Crittenden, American Express' chief financial officer.

The company previously had said it would provide Ameriprise with a capital infusion but hadn't detailed the amount.

American Express — famous for pumping huge amounts of money into its ad campaigns — said that more than $300 million of those expenses will be devoted to Ameriprise's planned marketing and rebranding efforts. Crittenden described that "very substantial" budget as "critical to Ameriprise's future success."

In addition to the $875 million in costs, American Express will face $70 million of separation expenses, $50 million of which will be recorded this year.

Under the spinoff, American Express shareholders will receive an as-yet-undetermined number of shares in the independent company.

The spinoff's tax-free status is conditioned on the two companies severing most of their ties within two years. Crittenden told analysts Tuesday that there are "literally thousands" of current relationships between American Express and the financial advisers unit, and most of them will have to be dissolved. In addition, Ameriprise will be restricted from being acquired or merging for two years.

Shares of American Express rose 79 cents, or 1.5 percent, to $54.93 Tuesday on the NYSE.