As Ken Lewis prepares to defend himself from fraud charges in New York, the retired chief executive of Bank of America Corp. may be sheltered from personal financial loss by several layers of special insurance. Legal and insurance experts say high-profile executives, such as Lewis, at large corporations are protected from serious financial harm in the case of a lawsuit because of cash set aside for their defense by the company and additional insurance, known as director’s and officer’s insurance. It has also been reported that recently Lewis individually secured additional insurance coverage for any damages not covered by the bank