Capital Accounts, Issuances of Equity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Buyback Program:
Common units acquired in connection with buyback program	$ 188	$ 250	$ 214
Phantom Unit Awards [Member]
Net Cash Proceeds from Sale of Common Units [Abstract]
Common units issued in connection with the vesting of phantom unit awards, net (in units)	4,662,539	4,571,333	3,936,437
2019 Buyback Program [Member]
Buyback Program:
Total of common units repurchased under a buyback program (in units)	7,244,540	10,166,923	9,891,956
Common units acquired in connection with buyback program	$ 188	$ 250	$ 214
Amount authorized under 2019 Buyback Program	2,000
Remaining available capacity under the 2019 Buyback Program	1,100
At-the-Market Registration [Member]
Registration Statements and Equity Offerings [Line Items]
Maximum common units authorized for issuance	2,500
Net Cash Proceeds from Sale of Common Units [Abstract]
Remaining units available for issuance	$ 2,500
Distribution Reinvestment Plan [Member]
Net Cash Proceeds from Sale of Common Units [Abstract]
Remaining units available for issuance (in units)	34,589,287
Employee Unit Purchase Plan [Member]
Registration Statements and Equity Offerings [Line Items]
Maximum common units authorized for issuance (in units)	23,000,000
Net Cash Proceeds from Sale of Common Units [Abstract]
Employer contribution to EUPP	$ 3	$ 3	$ 3
Remaining units available for issuance (in units)	15,027,935
Distribution Reinvestment and Employee Unit Purchase Plans [Member]
Net Cash Proceeds from Sale of Common Units [Abstract]
Number of common units purchased on the open market and delivered to participants (in units)	6,560,588	6,392,846	6,363,197