Capital Accounts - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended				9 Months Ended
	Nov. 14, 2025	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Oct. 31, 2025
Buyback Program:
Total of common units repurchased and retired under a buyback program (in units)		2,543,004	3,566,979	1,803,215
Cost of common units repurchased under 2019 buyback program		$ 80			$ 76	$ 250	$ 156
Proceeds from Issuance or Sale of Equity [Abstract]
Common units issued in connection with the vesting of phantom unit awards, net (in units)		113,097	220,829	4,989,490
Cash distributions paid to convertible preferred unitholders						$ 2
Paid in-kind distribution to third party (in units)		99	97	95		291
Paid -in-kind unit issued value (less than)						$ 1
Distribution per common unit (in dollars per unit)		$ 0.545
Annualized distribution per common unit (in dollars per unit)		$ 2.18
Cash payments made in connection with DERs						$ 33	$ 32
Forecast
Proceeds from Issuance or Sale of Equity [Abstract]
Cash distributions paid	$ 1,190
Cash payments made in connection with DERs	$ 11
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)						5,323,416
2019 Buyback Program
Buyback Program:
Amount authorized under 2019 Buyback Program		$ 2,000				$ 2,000
Total of common units repurchased and retired under a buyback program (in units)		2,543,004			2,646,351	7,913,198	5,452,767
Cost of common units repurchased under 2019 buyback program		$ 80			$ 76	$ 250	$ 156
Remaining available capacity under the 2019 Buyback Program		613				613
2019 Buyback Program | Subsequent Event
Buyback Program:
Amount authorized under 2019 Buyback Program								$ 5,000
Remaining available capacity under the 2019 Buyback Program								$ 3,600
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)						3,529,782
Employee Unit Purchase Plan
Proceeds from Issuance or Sale of Equity [Abstract]
Employer contribution to EUPP						$ 3