Fair Value Measurements and Guarantees (Tables)

6 Months Ended

Jun. 30, 2026

Fair Value Assets and Liabilities Measured On Recurring Basis [Table Text Block]

The following table presents, by level within the fair value hierarchy, certain of Williams’, Transco’s, and NWP’s significant financial assets and liabilities. The carrying values of cash and cash equivalents, accounts receivable, accounts payable, and commercial paper approximate fair value because of the short-term nature of these instruments. Therefore, these assets and liabilities are not presented in the following table.


					Fair Value Measurements Using
	Carrying Amount		Fair Value		Quoted Prices In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(Millions)
Assets (liabilities) at June 30, 2026:
Measured on a recurring basis:
ARO Trust - Transco	$	321	$	321	$	321	$	—	$	—
Commodity derivative assets (1)	266		631		392		98		141
Commodity derivative liabilities (1)	(309)		(919)		(536)		(213)		(170)
Equity securities	123		123		123		—		—


Additional disclosures:


Guarantees	(34)		(26)		—		(10)		(16)
Debt by issuer, including current portion:
Williams	(23,300)		(22,875)		—		(22,875)		—
Transco	(5,890)		(5,827)		—		(5,827)		—
NWP	(749)		(747)		—		(747)		—
MountainWest	(379)		(386)		—		(386)		—
Total debt	(30,318)		(29,835)		—		(29,835)		—

Assets (liabilities) at December 31, 2025:
Measured on a recurring basis:
ARO Trust - Transco	$	356	$	356	$	356	$	—	$	—
Commodity derivative assets (1)	336		722		431		158		133
Commodity derivative liabilities (1)	(340)		(915)		(497)		(270)		(148)

Additional disclosures:

Guarantees	(35)		(28)		—		(12)		(16)
Debt by issuer, including current portion:
Williams	(21,649)		(21,556)		—		(21,556)		—
Transco	(5,888)		(5,941)		—		(5,941)		—
NWP	(748)		(747)		—		(747)		—
MountainWest	(376)		(385)		—		(385)		—
Total debt	(28,661)		(28,629)		—		(28,629)		—

(1)The carrying amount is presented net of counterparty offsetting arrangements and collateral (see Note 8 – Commodity Derivatives).

Debt Securities, Trading, and Equity Securities, FV-NI

Investments within the ARO Trust were as follows:


	June 30, 2026				December 31, 2025
	Amortized Cost Basis		Fair Value		Amortized Cost Basis		Fair Value
	(Millions)
Money market fund	$	3	$	3	$	34	$	34
U.S. equity funds	38		145		53		169
International equity fund	32		58		32		51
Municipal bond fund	117		115		104		102
Total	$	190	$	321	$	223	$	356