Statements of Consolidated and Combined Equity and Partners' Capital (Parenthetical)
$ in Millions
2 Months Ended
Mar. 31, 2015
USD ($)
Net proceeds from IPO $ 1,168.4
Common Units | Limited Partner  
Net proceeds from IPO $ 1,168.4
Columbia OpCo  
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest Additional Ownership Interest 8.40%
Hardy Storage  
Equity Method Investment, Percent Not Contributed to Partnership 1.00%
Hardy Storage | Predecessor  
Equity Method Investment, Ownership Percentage 50.00%