Capital Accounts, Issuances of Equity (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			6 Months Ended
	Aug. 31, 2024	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Net Cash Proceeds from Sale of Common Units [Abstract]
Common units issued in connection with the vesting of phantom unit awards, net (in units)		162,867	4,679,377
Buyback Program:
Total of common units repurchased under a buyback program (in units)		1,419,581	1,386,835
Common units acquired in connection with buyback program		$ 40		$ 75	$ 80	$ 92
Long-Term Incentive Plan (2008) [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)					4,842,244
Senior Notes [Member] | Subsequent Event [Member]
Registration Statements and Equity Offerings [Line Items]
Debt issued under universal shelf registration	$ 2,500
2019 Buyback Program [Member]
Buyback Program:
Amount authorized under 2019 Buyback Program		2,000			$ 2,000
Remaining available capacity under the 2019 Buyback Program		$ 1,000			$ 1,000
Total of common units repurchased under a buyback program (in units)		1,419,581		2,910,121	2,806,416	3,592,710
Common units acquired in connection with buyback program		$ 40		$ 75	$ 80	$ 92
At-the-Market Registration [Member]
Registration Statements and Equity Offerings [Line Items]
Maximum common units authorized for issuance		2,500			2,500
Remaining units available for issuance		$ 2,500			2,500
Employee Unit Purchase Plan [Member]
Net Cash Proceeds from Sale of Common Units [Abstract]
Employer contribution to EUPP					$ 2
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)					3,364,678