Capital Accounts - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended			6 Months Ended
	Aug. 14, 2026	Jun. 30, 2026	Mar. 31, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025	Oct. 31, 2025	Jan. 31, 2019
Buyback Program:
Total of common units repurchased and retired under a buyback program (in units)		4,166,738	3,124,192
Cost of common units repurchased under 2019 buyback program		$ 159		$ 110	$ 275	$ 170
Proceeds from Issuance or Sale of Equity [Abstract]
Common units issued in connection with the vesting of phantom unit awards, net (in units)		125,636	4,866,420
Series A cumulative convertible preferred units outstanding (in units)		45,412			45,412		45,412
Cash distributions paid to convertible preferred unitholders					$ 2
Distribution per common unit (in dollars per unit)		$ 0.56
Annualized distribution per common unit (in dollars per unit)		$ 2.24
Cash payments made in connection with DERs					$ 23	$ 22
Forecast
Proceeds from Issuance or Sale of Equity [Abstract]
Cash distributions paid	$ 1,200
Cash payments made in connection with DERs	$ 12
Long-Term Incentive Plan (2008)
Proceeds from Issuance or Sale of Equity [Abstract]
Common units issued in connection with the vesting of phantom unit awards, net (in units)					4,992,056
2019 Buyback Program
Buyback Program:
Amount authorized under 2019 Buyback Program								$ 5,000	$ 2,000
Total of common units repurchased and retired under a buyback program (in units)		4,166,738		3,566,979	7,290,930	5,370,194
Cost of common units repurchased under 2019 buyback program		$ 159		$ 110	$ 275	$ 170
Remaining available capacity under the 2019 Buyback Program		3,300			3,300
At-the-Market Registration
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
Distribution Reinvestment and Employee Unit Purchase Plans
Proceeds from Issuance or Sale of Equity [Abstract]
Number of common units purchased on the open market and delivered to participants (in units)					2,040,782
Employee Unit Purchase Plan
Proceeds from Issuance or Sale of Equity [Abstract]
Employer contribution to EUPP					$ 2