Earnings Per Limited Partner Unit (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019		Sep. 30, 2020		Sep. 30, 2019
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss)	$ (163)	$ 133		$ (14)		$ 380
Net income (loss) attributable to noncontrolling interest	1	1		(6)		2
Series A Preferred Unit distributions	9	9		27		27
General partner interest in net income	0	0		0		0
Net Income (Loss) Attributable to Common Units (Note 5)	$ (173)	123		$ (35)		$ 351
Phantom units
Basic weighted average number of outstanding
Basic weighted average number of outstanding	2,000,000			2,000,000		1,000,000
Common Unit [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss) Attributable to Common Units (Note 5)	$ (173)	123		$ (35)		$ 351
Dilutive effect of Series A Preferred Unit distributions (2)	0	0		0		0
Diluted net income	$ (173)	$ 123		$ (35)		$ 351
Basic earnings (loss) per unit
Basic earnings (loss) per unit	$ (0.40)	$ 0.28		$ (0.08)		$ 0.81
Basic weighted average number of outstanding
Basic weighted average number of outstanding	437	437	[1]	437	[1]	436	[1]
Dilutive effect of Series A Preferred Units (in units)	0	0		0		0
Diluted weighted average number of outstanding units	437	437		437		436
Diluted earnings per unit	$ (0.40)	$ 0.28		$ (0.08)		$ 0.81

[1] Basic weighted average number of outstanding common units includes approximately two million time-based phantom units for both the three months ended September 30, 2020 and 2019, and two million and one million time-based phantom units for the nine months ended September 30, 2020 and 2019, respectively.(2)For the three and nine months ended September 30, 2020 and 2019, the issuance of “if-converted” common units attributable to the Series A Preferred Units were excluded in the calculation of diluted earnings (loss) per unit as the impact was anti-dilutive. (3)The contingent effect of performance unit awards is anti-dilutive for the three and nine months ended September 30, 2020. The dilutive effect of the performance unit awards was less than $0.01 per unit during the three and nine months ended September 30, 2019.