Net Income Per Limited Partner Unit (Schedule of Net Income By Class of Participating Securities) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Limited Partners' Capital Account [Line Items]
Distributions declared	$ 209	$ 186	$ 418	$ 370
Distributions less than net income	46	47	63	61
Net income (basic)	$ 255	$ 233	$ 481	$ 431
Common Units
Limited Partners' Capital Account [Line Items]
Weighted-average units outstanding—basic (in shares)	228,340,146	124,824,010	228,326,203	124,542,536
Dilutive effect of preferred units (in shares)	13,819,791	13,819,791	13,819,791	13,819,791
Weighted-average units outstanding—diluted (in shares)	242,159,937	138,643,801	242,145,994	138,362,327
Net income per limited partner unit—basic (in dollars per share)	$ 1.07	$ 1.23	$ 2.02	$ 2.19
Net income per limited partner unit—diluted (in dollars per share)	$ 1.05	$ 1.15	$ 1.99	$ 2.07
Limited Partner | Common Units
Limited Partners' Capital Account [Line Items]
Distributions declared	$ 200	$ 107	$ 399	$ 212
Distributions less than net income	46	46	63	60
Net income (basic)	246	153	462	272
Dilutive effect of preferred units	9	6	19	14
Net income (diluted)	255	159	481	286
Limited Partner | Preferred Units
Limited Partners' Capital Account [Line Items]
Distributions declared	9	9	19	19
Distributions less than net income	0	0	0	0
Net income (basic)	9		19	19
General Partner
Limited Partners' Capital Account [Line Items]
Distributions declared	$ 0	70	$ 0	139
Distributions less than net income		1		1
Net income (basic)		$ 71		$ 140