...NEW YORK (S&P Global Ratings) March 7, 2017--S&P Global Ratings said today it assigned its '###+' issue-level rating to Southern Natural Gas Co. LLC's proposed $400 million senior notes due in 2047. The partnership intends to use net proceeds of the offering to repay a portion of the 5.9% senior notes due April 1, 2017. Reported long-term debt outstanding debt is $1.2 billion as of December 2016. Houston¡based Southern Natural Gas Co. is a strategic natural gas pipeline joint venture with Kinder Morgan Inc. (KMI) and Southern Co. Our corporate credit rating on Southern is '###+', and the outlook is stable. For the corporate credit rating rationale, see the research update published on Sept. 02, 2016. RELATED CRITERIA + Criteria - Corporates - General: Methodology And Assumptions: Liquidity Descriptors For Global Corporate Issuers, Dec. 16, 2014 + Criteria - Corporates - Industrials: Key Credit Factors For The Midstream Energy Industry, Dec. 19, 2013 + Criteria - Corporates - General: Corporate...