Sears, Roebuck and Co. plans to offer the ultimate credit card, one "capable of handling practically all household financial transactions" and competing with every other card on the market, Sears Chairman Edward R. Telling disclosed last night.

With the super Sears card, customers will be able to deposit or withdraw funds at any Sears store; any branch of Sears' Allstate insurance company subsidiary; any office of Dean Witter Reynolds, the brokerage firm recently acquired by Sears; any office of Coldwell Banker, the Sears-owned real estate firm, or any other "outlet in the Sears family," Telling said.

In a futuristic speech prepared for delivery to the Economic Club of Chicago, Telling predicted Sears will become "as important a factor in financial services as we are in consumer sales."

The Sears chief also said the world's largest retailing enterprise intends to start an international trading company, patterned after multibillion-dollar Japanese trading firms, that will import and export goods all over the world.

The Sears-of-the-future forecast by Telling will be made possible by the rapidly evolving deregulation of banking that will create "a new financial service system," he asserted.

"You might as well try to stop Sears from selling in suburban stores as to try to keep new financial services away from the small saver," Telling said in what amounted to a challenge to the banking business.

"We might not always have the 15,000 banks that we have today," the approximate number of separate commercial banks in the United States, he noted.

Telling gave this list of financial innovations "on our planning list":

* "Opportunities for our customers to borrow money on their home equity" through some sort of Sears second mortgage.

* "Electronic funds transfers throughout the United States."

* "Eventually all outlets in the Sears family of companies can have the capacity to accept and disburse funds.

* "We will be among the first to have a truly universal financial card capable of handling practically all household financial transactions.

* "We will pioneer in two-way communications with the home, through computers and telephones, for financial transactions and consumer products as well."

As the nation's largest retailer, Sears has run out of room to grow in the general merchandise business and for several years has been diversifying to the financial services field.

Sears' first foray into finance was Allstate, now one of the nation's biggest insurance companies.

Before buying Coldwell Banker--the largest real estate firm in the country--and Dean Witter Reynolds--one of the biggest on Wall Street--Sears had picked up PMI, one of the major private mortgage insurance companies and Allstate Savings and Loan, with more than 100 branches in California.