“Petitioner Metropolitan Life Insurance Company (MetLife) serves as both an administrator and the insurer of Sears, Roebuck & Company's long-term disability insurance plan, an ERISA-governed employee benefit plan. See App. 182a-183a; 29 U.S.C. § 1003. The plan grants MetLife (as administrator) discretionary authority to determine whether an employee's claim for benefits is valid; it simultaneously provides that MetLife (as insurer) will itself pay valid benefit claims. App. 181a-182a.” Metropolitan Life Ins. Co. v. Glenn, 128 S.Ct. 2343, 2346 (2008)(J. Breyer).