The following table presents, by level within the fair value hierarchy, certain of our significant financial assets and liabilities. The carrying values of cash and cash equivalents, accounts receivable, and accounts payable 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 December 31, 2021:
Measured on a recurring basis:
ARO Trust investments	$	260	$	260	$	260	$	—	$	—
Commodity derivative assets (1)	84		84		2		81		1
Commodity derivative liabilities (1)	(488)		(488)		(69)		(403)		(16)
Additional disclosures:


Long-term debt, including current portion	(23,675)		(27,768)		—		(27,768)		—
Guarantees	(39)		(26)		—		(10)		(16)

Assets (liabilities) at December 31, 2020:
Measured on a recurring basis:
ARO Trust investments	$	235	$	235	$	235	$	—	$	—
Commodity derivative assets	3		3		1		2		—
Commodity derivative liabilities	(6)		(6)		(3)		(1)		(2)
Additional disclosures:

Long-term debt, including current portion	(22,344)		(27,043)		—		(27,043)		—
Guarantees	(40)		(27)		—		(11)		(16)

ARO Trust investments: Transco deposits a portion of its collected rates, pursuant to its rate case settlement, into an external trust that is specifically designated to fund future ARO’s. The ARO Trust invests in a portfolio of actively traded mutual funds that are measured at fair value on a recurring basis based on quoted prices in an active market and is reported in Regulatory assets, deferred charges, and other in our Consolidated Balance Sheet. Both realized and unrealized gains and losses are ultimately recorded as regulatory assets or liabilities.

Commodity derivatives: Commodity derivatives include exchange-traded contracts and OTC contracts, which consist of physical forwards, futures, and swaps that are measured at fair value on a recurring basis. We also have other derivatives related to asset management agreements and other contracts that require physical delivery.

Derivatives classified as Level 1 are valued using New York Mercantile Exchange (NYMEX) futures prices. Derivatives classified as Level 2 are valued using basis transactions that represent the cost to transport natural gas from a NYMEX delivery point to the contract delivery point. These transactions are based on quotes obtained either through electronic trading platforms or directly from brokers. Derivatives classified as Level 3 are valued using a combination of observable and unobservable inputs. Beginning in the third quarter of 2021 the fair value amounts are presented on a net basis and reflect the netting of asset and liability positions permitted under the terms of our master netting arrangements and cash held on deposit in margin accounts that we have received or remitted to collateralize certain derivative positions. Commodity derivative assets are reported in Other current assets and deferred charges and Regulatory assets, deferred charges, and other in our Consolidated Balance Sheet. Commodity derivative liabilities are reported in Accrued liabilities and Regulatory liabilities, deferred income, and other in our Consolidated Balance Sheet. See Note 18 – Derivatives for additional information on our derivatives.


	Year Ended December 31,
	2021		2020
	(Millions)
Balance at beginning of period	$	(2)	$	(2)
Realized and unrealized gains (losses):
Included in income (loss)	(62)		—

Purchases, issuances, and settlements	13		—
Acquired derivatives (Note 3)	24		—
Transfers out of Level 3	12		—
Balance at end of period	$	(15)	$	(2)

Long-term debt, including current portion: The disclosed fair value of our long-term debt is determined primarily by a market approach using broker quoted indicative period-end bond prices. The quoted prices are based on observable transactions in less active markets for our debt or similar instruments. The fair values of the financing obligations associated with our Dalton, Leidy South, and Atlantic Sunrise projects, which are included within long-term debt, were determined using an income approach (see Note 13 – Debt and Banking Arrangements).

Guarantees: Guarantees primarily consist of a guarantee we have provided in the event of nonpayment by our previously owned communications subsidiary, Williams Communications Group (WilTel), on a lease performance obligation that extends through 2042. Guarantees also include an indemnification related to a disposed operation.

To estimate the fair value of the WilTel guarantee, an estimated default rate is applied to the sum of the future contractual lease payments using an income approach. The estimated default rate is determined by obtaining the average cumulative issuer-weighted corporate default rate based on the credit rating of WilTel’s current owner and the term of the underlying obligation. The default rate is published by Moody’s Investors Service. The carrying value of the WilTel guarantee is reported in Accrued liabilities in our Consolidated Balance Sheet. The maximum potential undiscounted exposure is approximately $25 million at December 31, 2021. Our exposure declines systematically through the remaining term of WilTel’s obligation.

The fair value of the guarantee associated with the indemnification related to a disposed operation was estimated using an income approach that considered probability-weighted scenarios of potential levels of future performance. The terms of the indemnification do not limit the maximum potential future payments associated with the guarantee. The carrying value of this guarantee is reported in Regulatory liabilities, deferred income, and other in our Consolidated Balance Sheet.

We are required by our revolving credit agreement to indemnify lenders for certain taxes required to be withheld from payments due to the lenders and for certain tax payments made by the lenders. The maximum potential amount of future payments under these indemnifications is based on the related borrowings and such future payments cannot currently be determined. These indemnifications generally continue indefinitely unless limited by the underlying tax regulations and have no carrying value. We have never been called upon to perform under these indemnifications and have no current expectation of a future claim.

During the first quarter of 2020, we observed a significant decline in the publicly traded price of our common stock (NYSE: WMB), which declined 40 percent during the quarter, including a 26 percent decline in the month of March. These changes were generally attributed to macroeconomic and geopolitical conditions, including significant declines in crude oil prices driven by both surplus supply and a decrease in demand caused by the coronavirus (COVID-19) pandemic. As a result of these conditions, we performed an interim assessment of the goodwill associated with our Northeast G&P reporting unit as of March 31, 2020. This goodwill resulted from the March 2019 acquisition of UEOM (see Note 3 – Acquisitions).

The assessment considered the total fair value of the businesses within the Northeast G&P reporting unit, which was determined using income and market approaches. We utilized internally developed industry weighted-average discount rates and estimates of valuation multiples of comparable publicly traded gathering and processing companies. In assessing the fair value as of the March 31, 2020, measurement date, we were required to consider recent publicly available indications of value, which included lower observed publicly traded EBITDA market multiples as compared with recent history and significantly higher industry weighted-average discount rates. The fair value of the reporting unit was further reconciled to our estimated total enterprise value as of March 31, 2020, which considered observable valuation multiples of comparable publicly traded companies applied to each distinct business including the Northeast G&P reporting unit. This assessment indicated that the estimated fair value of the Northeast G&P reporting unit was below its carrying value, including goodwill. As a result of this Level 3 measurement, we recognized a full impairment charge of $187 million as of March 31, 2020, in Impairment of goodwill in our Consolidated Statement of Income. Our partner’s $65 million share of this impairment is reflected within Net income (loss) attributable to noncontrolling interests in our Consolidated Statement of Income (see Note 3 – Acquisitions).


					Impairments
					Year Ended December 31,
	Segment	Date of Measurement	Fair Value		2021		2020		2019
			(Millions)
Impairment of certain assets:
Certain capitalized project costs (1)	Transmission & Gulf of Mexico	June 30, 2021	$	1	$	2
Certain capitalized project costs (1)	Transmission & Gulf of Mexico	December 31, 2020	42				$	170
Certain gathering assets (2)	Northeast G&P	December 31, 2020	5				12
Certain pipeline project (3)	Transmission & Gulf of Mexico	December 31, 2019	22						$	354
Certain gathering assets (4)	West	December 31, 2019	25						20
Certain gathering assets (4)	West	June 30, 2019	40						59
Certain idle gathering assets (5)	West	March 31, 2019	—						12


Other impairments and write-downs (6)									19
Impairment of certain assets					$	2	$	182	$	464
Impairment of equity-method investments:
RMM (7)	West	December 31, 2020	$	421			$	108
RMM (8)	West	March 31, 2020	557				243
Brazos Permian II (8)	West	March 31, 2020	—				193
BRMH (9)	Northeast G&P	March 31, 2020	191				229
Appalachia Midstream Investments (9)	Northeast G&P	March 31, 2020	2,700				127
Aux Sable (9)	Northeast G&P	March 31, 2020	7				39
Laurel Mountain (9)	Northeast G&P	March 31, 2020	236				10
Discovery (9)	Transmission & Gulf of Mexico	March 31, 2020	367				97
Laurel Mountain (10)	Northeast G&P	September 30, 2019	242						$	79
Appalachia Midstream Investments (11)	Northeast G&P	September 30, 2019	102						17
Pennant (12)	Northeast G&P	August 31, 2019	11						17
UEOM (13)	Northeast G&P	March 17, 2019	1,210						74

Other									(1)
Impairment of equity-method investments					$	—	$	1,046	$	186

Conservation and the New Jersey Department of Environmental Protection have been denied and we have not refiled at this time. Beginning in May 2020, we discontinued capitalization of costs related to this project. Considering that the customer precedent agreements and FERC certificate for the project remain in effect, we had previously concluded that the probability of completing the project was sufficient to not require impairment. However, developments in the political and regulatory environments caused us to slightly lower that assessed probability such that the capitalized project costs now required impairment. The estimated fair value of the materials within the capitalized project costs at December 31, 2020 considered other internal uses and salvage values for the Property, plant, and equipment – net. The remaining capitalized costs were determined to have no fair value. The estimated fair value of certain capitalized project costs at June 30, 2021, was determined by a market approach, which incorporated an indication of interest by a third-party.

(2)Relates to a gathering system in the Marcellus Shale region, that was sold in 2021. The estimated fair value of the Property, plant, and equipment – net and Intangible assets – net of accumulated amortization was determined using a market approach, which incorporated an indication of interest by a third party. These inputs resulted in a fair value measurement within Level 2 of the fair value hierarchy.

(3)Relates to the Constitution proposed pipeline project extending from Susquehanna County, Pennsylvania, to the Iroquois Gas Transmission and the Tennessee Gas Pipeline systems in New York. Although Constitution received a certificate of public convenience and necessity from the FERC to construct and operate the proposed pipeline and obtained, among other approvals, a waiver of the water quality certification under Section 401 of the Clean Water Act for the New York portion of the project, the members of Constitution, following extensive evaluation and discussion, determined that the underlying risk-adjusted return for this greenfield pipeline project had diminished in such a way that further development was no longer supported. The estimated fair value of the Property, plant, and equipment – net was based on probability-weighted third-party quotes. Our partners’ $209 million share of this impairment is reflected within Net income (loss) attributable to noncontrolling interests in our Consolidated Statement of Income.

(4)Relates to a gas gathering system in the Eagle Ford Shale region for which we expected declines in asset utilization and possible idling of the gathering system. As a result, we measured the fair value of these assets at December 31, 2019 using a market approach. These inputs resulted in a fair value measurement within Level 2 of the fair value hierarchy. The estimated fair value of the Property, plant, and equipment – net at June 30, 2019, was determined using a market approach, which incorporated indications of interest from third parties.

(7)During the fourth quarter of 2020, RMM renegotiated service contracts with a significant customer in connection with the customer’s Chapter 11 bankruptcy proceedings. The renegotiated contracts result in lower service rates and lower projected future cash flows. As a result, we evaluated this investment for other-than-temporary impairment. The fair value was measured using an income approach. We utilized a discount rate of 18 percent in our analysis.

(8)Following the previously described declining market conditions during the first quarter of 2020, we evaluated these investments for other-than-temporary impairment. The fair value was measured using an income approach. Both investees operate in primarily oil-driven basins where significant expected reductions in producer activities led to reduced estimates of expected future cash flows. Our fair value estimates also reflected discount rates of approximately 17 percent for these investments. We also considered any debt held at

(9)Following the previously described declining market conditions during the first quarter of 2020, we evaluated these investments for other-than-temporary impairment. The impairments within our Northeast G&P segment are primarily associated with operations in wet-gas areas where producer drilling activities are influenced by NGL prices which historically trend with crude oil prices. The fair values of our investments in BRMH and Aux Sable Liquid Products LP (Aux Sable) were estimated using a market approach, reflecting valuation multiples ranging from 5.0x to 6.2x EBITDA (weighted-average 6.0x). The fair values of the other investments, including gathering systems that are part of Appalachia Midstream Investments, were estimated using an income approach, with discount rates ranging from 9.7 percent to 13.5 percent (weighted-average 12.6 percent). We also considered any debt held at the investee level, and its impact to fair value. The assumed valuation multiples and industry weighted-average discount rates utilized were both significantly influenced by the market declines previously discussed.

(10)Relates to a gas gathering system in the Marcellus Shale region that was adversely impacted by lower sustained forward natural gas price expectations and changes in expected producer activity. The estimated fair value was determined using an income approach. We utilized a discount rate of 10.2 percent in our analysis.

(13)The estimated fair value at March 17, 2019, was determined by a market approach based on the transaction price for the purchase of the remaining interest in UEOM as finalized just prior to the signing and closing of the acquisition in March 2019 (see Note 3 – Acquisitions). These inputs resulted in a fair value measurement within Level 2 of the fair value hierarchy.


	December 31,
	2021		2020
	(Millions)
NGLs, natural gas, and related products and services	$	486	$	470
Regulated interstate natural gas transportation and storage	274		254
Marketing of natural gas and NGLs (1)	609		167
Upstream activities	82		1
Accounts Receivable related to revenues from contracts with customers	1,451		892
Derivative receivables (2)	462		—
Other	65		107
Trade accounts and other receivables - net	$	1,978	$	999

Customers include producers, distribution companies, industrial users, gas marketers, and pipelines primarily located in the continental United States. As a general policy, collateral is not required for receivables with the exception of the marketing receivables discussed below. Customers’ financial condition and credit worthiness are evaluated regularly and, based upon this evaluation, we may obtain collateral to support receivables.

We use established credit policies to determine and monitor the creditworthiness of gas marketing and trading counterparties, including requirements to post collateral or other credit security, as well as the quality of pledged collateral. Collateral or credit security is most often in the form of cash or letters of credit from an investment-grade financial institution, but may also include U.S. government securities. We also utilize netting agreements whenever possible to mitigate exposure to gas marketing and trading counterparty credit risk. When more than one derivative transaction with the same counterparty is outstanding and a legally enforceable netting agreement exists with that counterparty, the “net” mark-to-market exposure represents a reasonable measure of our credit risk with that counterparty.