v3.7.0.1
Related-Party Transactions Related-Party Transactions, Summary of Affiliate Transactions (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 12 Months Ended
May 15, 2017
Apr. 19, 2017
Mar. 31, 2017
Mar. 31, 2016
Dec. 31, 2016
Distribution Made to Limited Partner, Cash Paid     $ 77.0    
Distribution Made to Limited Partner, Distributions Declared, Per Unit     $ 0.94 [1]   $ 0.91
Distribution Made to Limited Partner, Distribution Date         Feb. 14, 2017
Distribution Made to Limited Partner, Cash Distributions Paid     $ 94.0 $ 73.0  
Subsequent Event          
Distribution Made to Limited Partner, Declaration Date   Apr. 19, 2017      
Distribution Made to Limited Partner, Distribution Date [1] May 15, 2017        
Distribution Made to Limited Partner, Cash Distributions Paid $ 71.0        
Rockies Natural Gas Business Acquisition [Member]          
managing member or general partner, subsequent distribution amount forfeited     $ 12.5    
[1] This distribution was declared on April 19, 2017 and will be paid on the date of distribution. This distribution is net of $12.5 million of IDRs waived by TLGP for the three months ended March 31, 2017.