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		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Limited Partners' Capital Account [Line Items]
Distributions declared	$ 210	$ 206	$ 628	$ 576
Distributions more than net income attributable to the Partnership	(4)	31	59	92
Net income attributable to the Partnership	$ 206	$ 237	$ 687	$ 668
Limited Partners’ Common Units
Limited Partners' Capital Account [Line Items]
Weighted-average units outstanding—basic (in shares)	228,340,146	192,273,672	228,330,885	147,367,681
Dilutive effect of preferred units (in shares)	13,819,791	13,819,792	13,819,791	13,819,791
Weighted-average units outstanding—diluted (in shares)	242,159,937	206,093,464	242,150,676	161,187,472
Net income attributable to the Partnership per limited partner unit—basic (in dollars per share)	$ 0.86	$ 1.18	$ 2.88	$ 3.39
Net income attributable to the Partnership per limited partner unit—diluted (in dollars per share)	$ 0.85	$ 1.15	$ 2.84	$ 3.25
Limited Partner | Limited Partners’ Common Units
Limited Partners' Capital Account [Line Items]
Distributions declared	$ 200	$ 197	$ 599	$ 409
Distributions more than net income attributable to the Partnership	(4)	31	59	91
Net income attributable to the Partnership	196	228	658	500
Dilutive effect of preferred units	10	9	29	23
Net income attributable to the Partnership (diluted)	206	237	687	523
Limited Partner | Limited Partners’ Preferred Units
Limited Partners' Capital Account [Line Items]
Distributions declared	10	9	29	28
Distributions more than net income attributable to the Partnership	0	0	0	0
Net income attributable to the Partnership	10	9	29	28
General Partner (including IDRs)
Limited Partners' Capital Account [Line Items]
Distributions declared	$ 0	$ 0	$ 0	139
Distributions more than net income attributable to the Partnership				1
Net income attributable to the Partnership				$ 140