Partners' Equity - Schedule of Cash Distributions (Details) - USD ($) $ / shares in Units, $ in Millions		May 27, 2020	May 19, 2020	May 15, 2020	May 05, 2020	Feb. 25, 2020	Feb. 18, 2020	Feb. 14, 2020	Feb. 07, 2020	Nov. 26, 2019	Nov. 19, 2019	Nov. 14, 2019	Nov. 05, 2019	Aug. 27, 2019	Aug. 20, 2019	Aug. 14, 2019	Aug. 02, 2019	May 29, 2019	May 21, 2019	May 15, 2019	Apr. 29, 2019
Distribution Made to Limited Partner [Line Items]
Record Date							Feb. 18, 2020				Nov. 19, 2019				Aug. 20, 2019				May 21, 2019
Payment Date						Feb. 25, 2020				Nov. 26, 2019				Aug. 27, 2019				May 29, 2019
Cash distribution declared (in dollars per unit)						$ 0.3305
Distribution made to unitholders						$ 144
Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units | Preferred Units
Distribution Made to Limited Partner [Line Items]
Record Date									Feb. 07, 2020				Nov. 05, 2019				Aug. 02, 2019				Apr. 29, 2019
Payment Date								Feb. 14, 2020				Nov. 14, 2019				Aug. 14, 2019				May 15, 2019
Cash Distribution
Distribution Made to Limited Partner [Line Items]
Cash distribution declared (in dollars per unit)										$ 0.3305				$ 0.3305				$ 0.318
Distribution made to unitholders										$ 144				$ 144				$ 138
Cash Distribution | Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units | Preferred Units
Distribution Made to Limited Partner [Line Items]
Cash distribution declared (in dollars per unit)								$ 0.625				$ 0.625				$ 0.625				$ 0.625
Distribution made to unitholders								$ 9				$ 9				$ 9				$ 9
Subsequent Event | Cash Distribution | Series A 10% Fixed to Floating Non Cumulative Redeemable Perpetual Preferred Units | Preferred Units
Distribution Made to Limited Partner [Line Items]
Record Date	[1]				May 05, 2020
Payment Date	[1]			May 15, 2020
Cash distribution declared (in dollars per unit)	[1]			$ 0.625
Distribution made to unitholders	[1]			$ 9
Cash distribution (in dollars per unit)					$ 0.625
Forecast | Subsequent Event
Distribution Made to Limited Partner [Line Items]
Record Date	[2]		May 19, 2020
Payment Date	[2]	May 27, 2020
Distribution made to unitholders	[2]	$ 72
Forecast | Subsequent Event | Cash Distribution
Distribution Made to Limited Partner [Line Items]
Cash distribution declared (in dollars per unit)		$ 0.16525

[1] The Board of Directors declared a $0.625 per Series A Preferred Unit cash distribution on May 5, 2020, to be paid on May 15, 2020, to Series A Preferred unitholders of record at the close of business on May 5, 2020.

[2] The Board of Directors declared this $0.16525 per common unit cash distribution on May 5, 2020, to be paid on May 27, 2020 to common unitholders of record at the close of business on May 19, 2020.