Consolidated Statement of Equity $ in Millions	USD ($)
Beginning balance at Dec. 31, 2018	$ 784
Cash distribution to unitholders	(87)
Unit-based compensation	3
Partnership net income (loss)	109
Ending balance at Mar. 31, 2019	809
Beginning balance at Dec. 31, 2018	784
Partnership net income (loss)	230
Ending balance at Sep. 30, 2019	762
Beginning balance at Mar. 31, 2019	809
Cash distribution to unitholders	(88)
Unit-based compensation	3
Partnership net income (loss)	55
Ending balance at Jun. 30, 2019	779
Cash distribution to unitholders	(87)
Unit-based compensation	4
Partnership net income (loss)	66
Ending balance at Sep. 30, 2019	762
Beginning balance at Dec. 31, 2019	758
Cash distribution to unitholders	(88)
Unit-based compensation	4
Partnership net income (loss)	(128)
Ending balance at Mar. 31, 2020	546
Beginning balance at Dec. 31, 2019	758
Partnership net income (loss)	129
Ending balance at Sep. 30, 2020	635
Beginning balance at Mar. 31, 2020	546
Cash distribution to unitholders	(88)
Unit-based compensation	3
Partnership net income (loss)	157
Ending balance at Jun. 30, 2020	618
Cash distribution to unitholders	(88)
Unit-based compensation	4
Partners' Capital, Other	1
Partnership net income (loss)	100
Ending balance at Sep. 30, 2020	$ 635