Condensed Consolidated Statements of Partners' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Noncontrolling Interest [Member]	Series A Preferred Units [Member] Preferred Units	Common Unit [Member] Partners' Capital	AOCI Attributable to Parent	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjustment Common Unit [Member] Partners' Capital
Balance, beginning of period at Dec. 31, 2018	$ 7,618	$ 38	$ 362	$ 7,218	$ 0
Balance, beginning of period, units at Dec. 31, 2018			15	433
Changes in Partners' Capital
Net Income	123	1	$ 9	$ 113
Partners' Capital Account, Distributions	(148)	(1)	(9)	(138)
Partners' Capital Account, Unit-based Compensation, Net of Taxes	(10)			$ (10)
Equity-based compensation, net of units for employee taxes, units				2
Balance, end of period at Mar. 31, 2019	7,583	38	$ 362	$ 7,183	0
Balance, end of period, units at Mar. 31, 2019			15	435
Changes in Partners' Capital
Net Income	124	0	$ 9	$ 115
Other comprehensive loss	(3)				(3)
Partners' Capital Account, Distributions	(148)	(1)	(9)	(138)
Partners' Capital Account, Unit-based Compensation, Net of Taxes	3			$ 3
Equity-based compensation, net of units for employee taxes, units				0
Balance, end of period at Jun. 30, 2019	7,559	37	$ 362	$ 7,163	(3)
Balance, end of period, units at Jun. 30, 2019			15	435
Balance, beginning of period at Dec. 31, 2019	7,409	37	$ 362	$ 7,013	(3)	$ (3)	$ (3)
Balance, beginning of period, units at Dec. 31, 2019			15	435
Changes in Partners' Capital
Net Income	105	(7)	$ 9	$ 103
Other comprehensive loss	(6)				(6)
Partners' Capital Account, Distributions	(156)	(3)	(9)	(144)
Partners' Capital Account, Unit-based Compensation, Net of Taxes	3			$ 3
Equity-based compensation, net of units for employee taxes, units				0
Balance, end of period at Mar. 31, 2020	7,352	27	$ 362	$ 6,972	(9)
Balance, end of period, units at Mar. 31, 2020			15	435
Changes in Partners' Capital
Net Income	44	0	$ 9	$ 35
Partners' Capital Account, Distributions	(81)	0	(9)	(72)
Partners' Capital Account, Unit-based Compensation, Net of Taxes	2			$ 2
Equity-based compensation, net of units for employee taxes, units				0
Balance, end of period at Jun. 30, 2020	$ 7,317	$ 27	$ 362	$ 6,937	$ (9)
Balance, end of period, units at Jun. 30, 2020			15	435