...NEW YORK (Standard & Poor's) July 17, 2015--Standard & Poor's Ratings Services today assigned its 'A-' issue-level rating to U.S.-based waste services company Waste Management Inc.'s $2.25 billion senior unsecured revolving credit facility due 2020. All other ratings on Waste Management are unchanged, including the 'A-' long-term corporate credit rating. The outlook remains stable. For our complete corporate credit rating rationale, see the summary on Waste Management Inc. published Dec. 2, 2014, on RatingsDirect. RELATED CRITERIA AND RESEARCH Related Criteria + Methodology And Assumptions: Liquidity Descriptors For Global Corporate Issuers, Dec. 16, 2014 + Key Credit Factors For The Environmental Services Industry, Feb. 12, 2014 + Corporate Methodology, Nov. 19, 2013 + Corporate Methodology: Ratios And Adjustments, Nov. 19, 2013 + Methodology: Management And Governance Credit Factors For Corporate Entities And Insurers, Nov. 13, 2012 + 2008 Corporate Criteria: Rating Each Issue, April...