v3.5.0.2
Quarterly Financial Data (Unaudited) (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Quarterly Financial Data                      
Total revenues $ 292 $ 282 $ 275 $ 263 $ 190 $ 150 $ 133 $ 127 $ 1,112 [1] $ 600 [1] $ 313 [1]
Operating and maintenance expenses 132 113 111 99 108 78 68 59 455 [1] 313 [1] 188 [1]
Operating income 102 105 104 103 30 55 42 54 414 [1] 181 [1] 57 [1]
Net earnings (loss) 64 70 67 69 (15) 27 25 36 270 [1] 73 [1] 18 [1]
Limited partners’ interest in net earnings (loss) $ 46 $ 53 $ 50 $ 50 $ (25) $ 20 $ 26 $ 35 $ 199 [1] $ 56 [1] $ 68 [1]
Net earnings (loss) per limited partner unit:                      
Common - basic (dollars per unit) $ 0.49 [2] $ 0.62 [2] $ 0.60 [2] $ 0.63 [2] $ (0.34) [2] $ 0.33 [2] $ 0.45 [2] $ 0.64 [2] $ 2.33 [2] $ 0.96 [2] $ 1.48
Common - diluted (dollars per unit) $ 0.49 [2] $ 0.62 [2] $ 0.60 [2] $ 0.63 [2] (0.34) [2] 0.33 [2] 0.45 [2] 0.64 [2] 2.33 [2] 0.96 [2] 1.47
Subordinated - basic and diluted (dollars per unit)         $ 0.00 [2] $ 0.00 [2] $ 0.45 [2] $ 0.64 [2] $ 0.00 $ 0.62 [2] $ 1.35
[1] All periods include the historical results of the Predecessors. See Notes 1 and 2 for further discussion.
[2] The sum of four quarters may not equal annual results due to rounding or the quarterly number of shares outstanding.