Net Income Per Limited Partner Unit - Schedule of Allocation of Net Income to Arrive at Net Income Per Limited Partner Unit (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Limited Partners Capital Account [Line Items]
Net income	$ 137	$ 65
Less: Net income attributable to noncontrolling interests	5	1
Net income attributable to the Partnership	132	64
Distributions declared	119	106
Income (less than) / in excess of distributions	13	(42)
General Partner
Limited Partners Capital Account [Line Items]
Net income attributable to the Partnership	27	27
Distributions declared	26	28
Income (less than) / in excess of distributions	1	(1)
Limited Partners’ Common Units
Limited Partners Capital Account [Line Items]
Net income attributable to the Partnership	105	37
Distributions declared	93	78
Income (less than) / in excess of distributions	$ 12	$ (41)