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								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Distribution Made To Limited Partner [Line Items]
Distributions declared									$ 552	$ 469	$ 292
Income (less than)/in excess of distributions									(24)	(5)	3
Net income attributable to the Partnership	$ 140	$ 141	$ 115	$ 132	$ 140	$ 149	$ 111	$ 64	528	464	295
Net income per limited partner unit:
Basic and diluted (in dollars per share)	$ 0.37	$ 0.45	$ 0.38	$ 0.47	$ 0.45	$ 0.50	$ 0.35	$ 0.18
General Partner
Distribution Made To Limited Partner [Line Items]
Distributions declared									148	135	64
Income (less than)/in excess of distributions									(1)	(1)	0
Net income attributable to the Partnership									147	134	64
Common
Distribution Made To Limited Partner [Line Items]
Distributions declared									404	334	228
Income (less than)/in excess of distributions									(23)	(4)	3
Net income attributable to the Partnership									$ 381	$ 330	$ 231
Weighted average units outstanding:
Basic and diluted (in shares)									229.2	220.3	180.4
Net income per limited partner unit:
Basic and diluted (in dollars per share)									$ 1.66	$ 1.50	$ 1.28