Does this mean they have $3.3 billion in current/potential liquidity?
"...In the past three months, MarkWest has successfully raised $1.5 billion in net proceeds from debt and equity transactions. In addition, MarkWest is currently undrawn on its $1.2 billion credit facility and has the ability to issue common units under its $600 million continuous equity program. These transactions, coupled with the execution of the Amended LLC Agreement, provide MarkWest with significant liquidity to fund the majority of its 2013 capital plan. ..."
No. i'm guessing that the debt proceeds were used to refinance existing debt, which has already been invested in projects. MWE's current liquidity = undrawn credit facility (plus whatever debt or equity the market is willing to purchase from them.)