Net Income Per Limited Partner Unit - Schedule of Basic and Diluted Net Income Per Unit (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Distribution Made To Limited Partner [Line Items]
Distributions declared	$ 162	$ 119
Income (less than) / in excess of distributions	(24)	13
Net income attributable to the Partnership	138	132
General Partner
Distribution Made To Limited Partner [Line Items]
Distributions declared	55	26
Income (less than) / in excess of distributions	0	1
Net income attributable to the Partnership	55	27
Limited Partners’ Common Units
Distribution Made To Limited Partner [Line Items]
Distributions declared	107	93
Income (less than) / in excess of distributions	(24)	12
Net income attributable to the Partnership	$ 83	$ 105
Weighted average units outstanding (in millions)
Weighted average units outstanding, basic and diluted (in shares)	233.3	223.8
Net income per Limited Partner Unit (in dollars)
Net income per Limited Partner unit, basic and diluted (in dollars per share)	$ 0.36	$ 0.47