Annual report pursuant to Section 13 and 15(d)

Summarized Quarterly Financial Data (unaudited) (Details)

v3.8.0.1
Summarized Quarterly Financial Data (unaudited) (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]                      
Revenues $ 1,518 $ 903 $ 992 $ 891 $ 551 $ 331 $ 151 $ 67 $ 4,304 $ 1,100 $ 270
Income (loss) from operations 540 197 200 219 199 48 13 (10) 1,156 250 3
Net income (loss) $ 374 $ 23 $ 46 $ 47 $ 86 $ (82) $ (100) $ (75) $ 490 $ (171) $ (319)
Net income (loss) per common unit—basic and diluted $ 0.76 [1] $ (1.10) [1] $ (3.71) [1] $ (0.80) [1] $ 0.07 [1] $ (0.27) [1] $ (0.21) [1] $ (0.08) [1] $ (1.32) $ (0.20) $ (0.43)
[1] The sum of the quarterly net income (loss) per common unit may not equal the full year amount as the undistributed income and loss allocations and computations of the weighted average common units outstanding for basic and diluted common units outstanding for each quarter and the full year are performed independently.