WASHINGTON — Discover Financial Services has agreed to pay $200 million in refunds to more than 3.5 million cardholders who bought credit-protection services over the phone, plus another $14 million in civil penalties to banking regulators.

The Consumer Financial Protection Bureau and the Federal Deposit Insurance Corp. jointly investigated Discover for deceptive telemarketing and sales practices, including misleading customers into thinking the services, like identity theft protection and credit score tracking, were free.

While neither admitting nor denying the allegations, Discover agreed to not engage in similar acts in the future and to fully inform potential customers of all of the costs and conditions of telemarketed or otherwise advertised products and services. The company also agreed to strengthen its compliance and audit programs.

The agencies said that from December 2007 through August 2011, Discover marketed the products, which also included payment protection and wallet protection services, to its credit-card customers by implying that they were being offered a free benefit rather than having to pay for a service.

Discover billed the fees for the services directly to the customers’ credit cards.

Those actions violated Section 5 of the Federal Trade Commission Act, and portions of the Consumer Financial Protection Act, which was part of the Dodd-Frank financial regulation law enacted in response to the financial crisis. The FDIC also charged Discover with engaging in unsafe or unsound banking practices.

The enforcement action is the second by the consumer bureau since it started up in July 2011. The bureau and the Office of the Comptroller of the Currency in July jointly charged Capital One, the bank and credit card company, with similar deceptive practices. Capital One agreed to pay a total of $150 million in customer refunds and $60 million in fines to the two regulators.

Richard Cordray, the director of the Consumer Financial Protection Bureau, said the agency expected that more such enforcement actions would follow.

“We are signaling as clearly as we can that other financial institutions should review their marketing practices to ensure that they are not deceiving or misleading consumers into purchasing financial products or services,” he said.

David Nelms, chairman and chief executive of Discover, said in a statement: “We have worked hard to earn the loyalty of our card members and we are committed to marketing our products responsibly. As always, we will continue to strive to deliver the highest standards of customer service and satisfaction.”

Current and former Discover customers will not have to take any action to receive the refunds, the regulatory agencies said. Current cardholders will receive a refund directly to their account, and former cardholders will receive a check or have any outstanding balance reduced by the amount of the refund.

The amounts of the refunds will depend on when customers purchased and how long they held the included products, the agencies said.

Customers who were enrolled in a product for less than one year will receive the total amount of product fees charged, while those enrolled for more than one year will receive 90 days of fees. Only those customers who were charged for the services but did not use them are eligible.