Public Service Co Of Colorado 10-K 23 Feb 22 2021 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 23, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-03280
Entity Registrant Name	PUBLIC SERVICE CO OF COLORADO
Entity Incorporation, State or Country Code	CO
Entity Tax Identification Number	84-0296600
Entity Address, Address Line One	1800 Larimer, Suite 1100
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80202
City Area Code	303
Local Phone Number	571-7511
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		100
Entity Central Index Key	0000081018
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Public Float			$ 0

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Auditor Information [Abstract]
Auditor Name	DELOITTE & TOUCHE LLP
Auditor Firm ID	34
Auditor Location	Minneapolis, Minnesota

Accounting Pronouncements

Accounting Pronouncements	12 Months Ended
	Dec. 31, 2021
Accounting Standards Update and Change in Accounting Principle [Abstract]
Accounting Pronouncements	Recently Adopted Credit Losses — In 2016, the FASB issued Financial Instruments - Credit Losses, Topic 326 (ASC Topic 326), which changes how entities account for losses on receivables and certain other assets. The guidance requires use of a current expected credit loss model, which may result in earlier recognition of credit losses than under previous accounting standards.

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating revenues
Electric	$ 3,413	$ 3,116	$ 3,033
Natural gas	1,355	1,024	1,161
Other	47	43	43
Total operating revenues	4,815	4,183	4,237
Operating expenses
Electric fuel and purchased power	1,336	1,132	1,083
Cost of natural gas sold and transported	606	374	526
Cost of sales — steam and other	15	13	17
Operating and maintenance expenses	831	811	810
Demand side management expenses	132	141	136
Depreciation and amortization	744	655	602
Taxes (other than income taxes)	256	234	206
Total operating expenses	3,920	3,360	3,380
Operating income	895	823	857
Other income (expense), net	4	(1)	3
Allowance for funds used during construction — equity	28	35	22
Interest charges and financing costs
Interest charges — includes other financing costs of $8, $7 and $7, respectively	(243)	(238)	(235)
Allowance for funds used during construction — debt	(9)	(14)	(11)
Total interest charges and financing costs	234	224	224
Income before income taxes	693	633	658
Income tax expense	33	45	80
Net income	660	588	578
Other financing costs	$ 8	$ 7	$ 7

CONSOLIDATED STATEMENTS OF IN_2

CONSOLIDATED STATEMENTS OF INCOME (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Other financing costs	$ 8	$ 7	$ 7

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Comprehensive income:
Net income	$ 660	$ 588	$ 578
Pension and retiree medical benefits:
Reclassification of loss (gain) to net income, net of tax of $—, $1 and $(1), respectively	0	2	(3)
Derivative instruments:
Reclassification of loss to net income, net of tax of $—, $— and $—, respectively	2	1	2
Total other comprehensive income (loss)	2	3	(1)
Total comprehensive income	662	591	577
Defined Benefit Plan Reclassification Adjustment from AOCI, Tax	0	1	(1)
Reclassification Adjustment from AOCI on Derivatives, Tax	0	0	0
Net income	660	588	578
Reclassification of loss (gain) to net income, net of tax of $—, $1 and $(1), respectively	0	2	(3)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	(2)	(1)	(2)
Total other comprehensive income (loss)	2	3	(1)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 662	$ 591	$ 577

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Defined Benefit Plan Reclassification Adjustment from AOCI, Tax	$ 0	$ 1	$ (1)
Reclassification Adjustment from AOCI on Derivatives, Tax	$ 0	$ 0	$ 0

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Operating activities
Net income	$ 660	$ 588	$ 578
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	754	656	607
Deferred income taxes	21	2	97
Amortization of investment tax credits	11	0	0
Allowance for equity funds used during construction	(28)	(35)	(22)
Provision for bad debts	26	24	17
Net realized and unrealized hedging and derivative transactions	(44)	(14)	62
Changes in operating assets and liabilities:
Accounts receivable	(58)	(51)	(22)
Accrued unbilled revenues	(52)	(5)	20
Inventories	(71)	(27)	(27)
Prepayments and other	(23)	(8)	(29)
Accounts payable	66	(14)	(44)
Net regulatory assets and liabilities	(526)	58	35
Other current liabilities	30	45	0
Pension and other employee benefit obligations	(53)	(41)	(47)
Other, net	14	(4)	3
Net cash provided by operating activities	727	1,174	1,228
Investing activities
Utility capital/construction expenditures	(1,604)	(1,671)	(1,691)
Investments in utility money pool arrangement	(273)	(122)	(641)
Repayments from utility money pool arrangement	273	122	641
Net cash used in investing activities	(1,604)	(1,671)	(1,691)
Financing activities
Proceeds from (repayments of) short-term borrowings, net	11	136	(307)
Borrowings under utility money pool arrangement	743	1,189	100
Repayments under utility money pool arrangement	(800)	(1,171)	(61)
Proceeds from issuance of long-term debt	737	735	928
Repayments of long-term debt	0	(400)	(400)
Capital contributions from parent	650	856	638
Dividends paid to parent	(467)	(831)	(457)
Net cash provided by financing activities	874	514	441
Net change in cash and cash equivalents	(3)	17	(22)
Cash, cash equivalents and restricted cash at beginning of period	28	11	33
Cash, cash equivalents and restricted cash at end of period	25	28	11
Supplemental disclosure of cash flow information:
Cash paid for interest (net of amounts capitalized)	(230)	(211)	(209)
Cash paid for income taxes, net	(14)	(23)	(5)
Supplemental disclosure of non-cash investing and financing transactions:
Accrued property, plant and equipment additions	157	197	234
Inventory transfers to property, plant and equipment	10	35	32
Operating lease right-of-use assets	0	14	654
Allowance for equity funds used during construction	28	35	22
Net income	660	588	578
Depreciation, Amortization and Accretion, Net	754	656	607
Deferred Income Tax Expense (Benefit)	21	2	97
Amortization of investment tax credits	11	0	0
Allowance for funds used during construction — equity	28	35	22
Provision for bad debts	26	24	17
Gain (loss) on hedging and derivative transactions	44	14	(62)
Increase (Decrease) in Accounts and Other Receivables	58	51	22
Increase (Decrease) in Accrued Unbilled Revenues	52	5	(20)
Increase (Decrease) in Inventories	71	27	27
Increase (Decrease) in Prepaid Expense and Other Assets	23	8	29
Increase (Decrease) in Accounts Payable	66	(14)	(44)
Increase (Decrease) in Regulatory Assets and Liabilities	526	(58)	(35)
Increase (Decrease) in Other Current Liabilities	30	45	0
Increase (Decrease) in Employee Related Liabilities	(53)	(41)	(47)
Other, net	14	(4)	3
Net Cash Provided by (Used in) Operating Activities	727	1,174	1,228
Payments to Acquire Productive Assets	1,604	1,671	1,691
Investments In Utility Money Pool Arrangement	273	122	641
Repayments From Utility Money Pool Arrangement	273	122	641
Net Cash Provided by (Used in) Investing Activities	(1,604)	(1,671)	(1,691)
Proceeds from (repayments of) short-term borrowings, net	11	136	(307)
Borrowings Under Utility Money Pool Arrangement	743	1,189	100
Repayments Under Utility Money Pool Arrangement	800	1,171	61
Proceeds from issuance of long-term debt	737	735	928
Repayments of Long-term Debt	0	400	400
Capital contributions from parent	650	856	638
Payments of Ordinary Dividends, Common Stock	467	831	457
Net Cash Provided by (Used in) Financing Activities	874	514	441
Net change in cash and cash equivalents	(3)	17	(22)
Cash, cash equivalents and restricted cash at end of period	25	28	11
Interest Paid, Excluding Capitalized Interest, Operating Activities	230	211	209
Income Taxes Paid, Net	14	23	5
Accrued property, plant and equipment additions	157	197	234
Inventory transfers to property, plant and equipment	10	35	32
Operating lease right-of-use assets	0	14	654
Allowance for equity funds used during construction	$ 28	$ 35	$ 22

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents		$ 25
Cash, cash equivalents and restricted cash at end of period		25	$ 28
Accounts receivable, net		374	342
Accounts receivable from affiliates		13	8
Accrued unbilled revenues		350	298
Inventories		245	189
Regulatory assets		353	121
Derivative instruments		39	21
Prepayments and other		104	82
Total current assets		1,503	1,089
Property, plant and equipment, net		18,444	17,470
Other assets
Regulatory assets		1,293	1,059
Derivative instruments		27	16
Operating lease right-of-use assets		409	500
Other		246	231
Total other assets		1,975	1,806
Total assets		21,922	20,365
Current liabilities
Current portion of long-term debt		300	0
Borrowings under utility money pool arrangement		0	57
Short-term debt		147	136
Accounts payable		531	452
Accounts payable to affiliates		69	58
Regulatory liabilities	[1]	95	100
Taxes accrued		252	251
Accrued interest		58	61
Dividends payable to parent		104	105
Derivative instruments		30	27
Operating lease liabilities		84	97
Other		109	84
Total current liabilities		1,779	1,428
Deferred credits and other liabilities
Deferred income taxes		1,960	1,897
Regulatory liabilities	[1]	2,397	2,337
Asset retirement obligations		422	399
Derivative instruments		29	51
Customer advances		160	168
Pension and employee benefit obligations		23	161
Operating lease liabilities		351	432
Other		190	176
Total deferred credits and other liabilities		5,532	5,621
Commitments and contingencies
Capitalization
Long-term debt		6,167	5,724
Common stock — 100 shares authorized of $0.01 par value; 100 shares outstanding at Dec. 31, 2021 and Dec. 31, 2020, respectively		$ 0	$ 0
Common Stock, Shares Authorized		100	100
Common Stock, Par or Stated Value Per Share		$ 0.01	$ 0.01
Common Stock, Shares, Outstanding		100	100
Additional paid in capital		$ 6,426	$ 5,770
Retained earnings		2,040	1,846
Accumulated other comprehensive loss		(22)	(24)
Total common stockholder's equity		8,444	7,592
Total liabilities and stockholder's equity		$ 21,922	$ 20,365
[1]	Revenue subject to refund of $2 million for 2021 is included in other current liabilities and none for 2020

CONSOLIDATED STATEMENTS OF COMM

CONSOLIDATED STATEMENTS OF COMMON STOCKHOLDER'S EQUITY - USD ($) $ in Millions	Total	Common stock	Additional Paid In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance (in shares) at Dec. 31, 2018		100
Beginning Balance at Dec. 31, 2018	$ 6,298	$ 0	$ 4,341	$ 1,983	$ (26)
Increase (Decrease) in Stockholder's Equity
Net income	578			578
Total other comprehensive income (loss)	(1)				(1)
Common dividends declared to parent	(478)			(478)
Contribution of capital by parent	599		599
Balance (in shares) at Dec. 31, 2019		100
Ending Balance at Dec. 31, 2019	6,996	$ 0	4,940	2,083	(27)
Increase (Decrease) in Stockholder's Equity
Net income	588			588
Total other comprehensive income (loss)	3				3
Common dividends declared to parent	(824)			(824)
Contribution of capital by parent	$ 830		830
Balance (in shares) at Dec. 31, 2020	100	100
Ending Balance at Dec. 31, 2020	$ 7,592	$ 0	5,770	1,846	(24)
Increase (Decrease) in Stockholder's Equity
Net income	660			660
Total other comprehensive income (loss)	2				2
Common dividends declared to parent	(466)			(466)
Contribution of capital by parent	$ 656		656
Balance (in shares) at Dec. 31, 2021	100	100
Ending Balance at Dec. 31, 2021	$ 8,444	$ 0	$ 6,426	2,040	$ (22)
Increase (Decrease) in Stockholder's Equity
Adoption of ASC Topic 326	$ (1)			$ (1)

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	General — PSCo is engaged in the regulated generation, purchase, transmission, distribution and sale of electricity and in the regulated purchase, transportation, distribution and sale of natural gas. PSCo’s consolidated financial statements include its wholly-owned subsidiaries. In the consolidation process, all intercompany transactions and balances are eliminated. PSCo has investments in several plants and transmission facilities jointly owned with nonaffiliated utilities. PSCo’s proportionate share of jointly owned facilities is recorded as property, plant and equipment on the consolidated balance sheets, and PSCo’s proportionate share of the operating costs associated with these facilities is included in its consolidated statements of income. PSCo’s consolidated financial statements are presented in accordance with GAAP. All of PSCo’s underlying accounting records also conform to the FERC uniform system of accounts or to systems required by various state regulatory commissions. Certain amounts in the consolidated financial statements or notes have been reclassified for comparative purposes; however, such reclassifications did not affect net income, total assets, liabilities, equity or cash flows. PSCo has evaluated events occurring after Dec. 31, 2021 up to the date of issuance of these consolidated financial statements. These statements contain all necessary adjustments and disclosures resulting from that evaluation. Use of Estimates — PSCo uses estimates based on the best information available in recording transactions and balances resulting from business operations. Estimates are used for items such as plant depreciable lives or potential disallowances, AROs, certain regulatory assets and liabilities, tax provisions, uncollectible amounts, environmental costs, unbilled revenues, jurisdictional fuel and energy cost allocations and actuarially determined benefit costs. Recorded estimates are revised when better information becomes available or actual amounts can be determined. Revisions can affect operating results. Regulatory Accounting — PSCo accounts for income and expense items in accordance with accounting guidance for regulated operations . Under this guidance: • Certain costs, which would otherwise be charged to expense or other comprehensive income, are deferred as regulatory assets based on the expected ability to recover the costs in future rates. • Certain credits, which would otherwise be reflected as income or other comprehensive income, are deferred as regulatory liabilities based on the expectation the amounts will be returned to customers in future rates, or because the amounts were collected in rates prior to the costs being incurred. Estimates of recovering deferred costs and returning deferred credits are based on specific ratemaking decisions or precedent for each item. Regulatory assets and liabilities are amortized consistent with the treatment in the rate setting process. If changes in the regulatory environment occur, PSCo may no longer be eligible to apply this accounting treatment and may be required to eliminate regulatory assets and liabilities from its balance sheet. Such changes could have a material effect on PSCo’s results of operations, financial condition and cash flows. See Note 4 for further information. Income Taxes — PSCo accounts for income taxes using the asset and liability method, which requires recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. PSCo defers income taxes for all temporary differences between pretax financial and taxable income and between the book and tax bases of assets and liabilities. PSCo uses rates that are scheduled to be in effect when the temporary differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in the period that includes the enactment date. The effects of PSCo’s tax rate changes are generally subject to a normalization method of accounting. Therefore, the revaluation of most of its net deferred taxes upon a tax rate reduction results in the establishment of a net regulatory liability, which would be refundable to utility customers over the remaining life of the related assets. PSCo anticipates that a tax rate increase would result in the establishment of a regulatory asset, subject to an evaluation of whether future recovery is expected. Tax credits are recorded when earned unless there is a requirement to defer the benefit and amortize it over the book depreciable lives of the related property. The requirement to defer and amortize tax credits only applies to federal ITCs related to public utility property. Utility rate regulation also has resulted in the recognition of regulatory assets and liabilities related to income taxes. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax asset will not be realized. PSCo follows the applicable accounting guidance to measure and disclose uncertain tax positions that it has taken or expects to take in its income tax returns. PSCo recognizes a tax position in its consolidated financial statements when it is more likely than not that the position will be sustained upon examination based on the technical merits of the position. Recognition of changes in uncertain tax positions are reflected as a component of income tax expense. PSCo reports interest and penalties related to income taxes within other (expense) income or interest charges in the consolidated statements of income. Xcel Energy Inc. and its subsidiaries, including PSCo, file consolidated federal income tax returns as well as consolidated or separate state income tax returns. Federal income taxes paid by Xcel Energy Inc. are allocated to its subsidiaries based on separate company computations. A similar allocation is made for state income taxes paid by Xcel Energy Inc. in connection with consolidated state filings. Xcel Energy Inc. also allocates its own income tax benefits to its direct subsidiaries. See Note 7 for further information. Property, Plant and Equipment and Depreciation in Regulated Operations — Property, plant and equipment is stated at original cost. The cost of plant includes direct labor and materials, contracted work, overhead costs and AFUDC. The cost of plant retired is charged to accumulated depreciation and amortization. Amounts recovered in rates for future removal costs are recorded as regulatory liabilities. Significant additions or improvements extending asset lives are capitalized, while repairs and maintenance costs are charged to expense as incurred. Maintenance and replacement of items determined to be less than a unit of property are charged to operating expenses as incurred. Planned maintenance activities are charged to operating expense unless the cost represents the acquisition of an additional unit of property or the replacement of an existing unit of property. Property, plant and equipment is tested for impairment when it is determined that the carrying value of the assets may not be recoverable. A loss is recognized in the current period if it becomes probable that part of a cost of a plant under construction or recently completed plant will be disallowed for recovery from customers and a reasonable estimate of the disallowance can be made. For investments in property, plant and equipment that are abandoned and not expected to go into service, incurred costs and related deferred tax amounts are compared to the discounted estimated future rate recovery, and a loss is recognized, if necessary. PSCo records depreciation expense using the straight-line method over the plant’s commission-approved useful life. Actuarial life studies are performed and submitted to the state and federal commissions for review. Upon acceptance by the various commissions, the resulting lives and net salvage rates are used to calculate depreciation. Plant removal costs are recovered in rates as authorized by the appropriate regulatory entities. The amount of removal costs is based on current factors used in existing depreciation rates. Depreciation expense, expressed as a percentage of average depreciable property, was approximately 3.2% in 2021, 3.1% in 2020 and 2.9% in 2019. See Note 3 for further information. AROs — PSCo accounts for AROs under accounting guidance that requires a liability for the fair value of an ARO to be recognized in the period in which it is incurred if it can be reasonably estimated, with the offsetting associated asset retirement costs capitalized as a long-lived asset. The liability is generally increased over time by applying the effective interest method of accretion, and the capitalized costs are depreciated over the useful life of the long-lived asset. Changes resulting from revisions to the timing or amount of expected asset retirement cash flows are recognized as an increase or a decrease in the ARO. See Note 10 for further information. Benefit Plans and Other Postretirement Benefits — PSCo maintains pension and postretirement benefit plans for eligible employees. Recognizing the cost of providing benefits and measuring the projected benefit obligation of these plans requires management to make various assumptions and estimates. Certain unrecognized actuarial gains and losses and unrecognized prior service costs or credits are deferred as regulatory assets and liabilities, rather than recorded as other comprehensive income, based on regulatory recovery mechanisms. See Note 9 for further information. Environmental Costs — Environmental costs are recorded when it is probable PSCo is liable for remediation costs and the liability can be reasonably estimated. Costs are deferred as a regulatory asset if it is probable that the costs will be recovered from customers in future rates. Otherwise, the costs are expensed. For certain environmental costs related to facilities currently in use, such as for emission-control equipment, the cost is capitalized and depreciated over the life of the plant. Estimated remediation costs are regularly adjusted as estimates are revised and remediation proceeds. If other participating potentially responsible parties exist and acknowledge their potential involvement with a site, costs are estimated and recorded only for PSCo’s expected share of the cost. Future costs of restoring sites are treated as a capitalized cost of plant retirement. The depreciation expense levels recoverable in rates include a provision for removal expenses. Removal costs recovered in rates before the related costs are incurred are classified as a regulatory liability. See Note 10 for further information. Revenue from Contracts with Customers — Performance obligations related to the sale of energy are satisfied as energy is delivered to customers. PSCo recognizes revenue that corresponds to the price of the energy delivered to the customer. The measurement of energy sales to customers is generally based on the reading of their meters, which occurs systematically throughout the month. At the end of each month, amounts of energy delivered to customers since the date of the last meter reading are estimated, and the corresponding unbilled revenue is recognized. PSCo does not recognize a separate financing component of its collections from customers as contract terms are short-term in nature. PSCo presents its revenues net of any excise or sales taxes or fees. See Note 6 for further information. Cash and Cash Equivalents — PSCo considers investments in instruments with a remaining maturity of three months or less at the time of purchase to be cash equivalents. Accounts Receivable and Allowance for Bad Debts — Accounts receivable are stated at the actual billed amount net of an allowance for bad debts. PSCo establishes an allowance for uncollectible receivables based on a policy that reflects its expected exposure to the credit risk of customers. As of Dec. 31, 2021 and 2020, the allowance for bad debts was $40 million and $29 million, respectively. Inventory — Inventory is recorded at average cost and consisted of the following: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 Inventories Materials and supplies $ 70 $ 63 Fuel 71 73 Natural gas 104 53 Total inventories $ 245 $ 189 Fair Value Measurements — PSCo presents cash equivalents, interest rate derivatives and commodity derivatives at estimated fair values in its consolidated financial statements. Cash equivalents are recorded at cost plus accrued interest; money market funds are measured using quoted NAVs. For interest rate derivatives, quoted prices based primarily on observable market interest rate curves are used to establish fair value. For commodity derivatives, the most observable inputs available are generally used to determine the fair value of each contract. In the absence of a quoted price, PSCo may use quoted prices for similar contracts or internally prepared valuation models to determine fair value. For the pension and postretirement plan assets, published trading data and pricing models, generally using the most observable inputs available, are utilized to estimate fair value for each security. See Notes 8 and 9 for further information. Derivative Instruments — PSCo uses derivative instruments in connection with its interest rate, utility commodity price and commodity trading activities, including forward contracts, futures, swaps and options. Any derivative instruments not qualifying for the normal purchases and normal sales exception are recorded on the consolidated balance sheets at fair value as derivative instruments. Classification of changes in fair value for those derivative instruments is dependent on the designation of a qualifying hedging relationship. Changes in fair value of derivative instruments not designated in a qualifying hedging relationship are reflected in current earnings or as a regulatory asset or liability. Classification as a regulatory asset or liability is based on commission approved regulatory recovery mechanisms. Gains or losses on commodity trading transactions are recorded as a component of electric operating revenues and interest rate hedging transactions are recorded as a component of interest expense. Normal Purchases and Normal Sales — PSCo enters into contracts for purchases and sales of commodities for use in its operations. At inception, contracts are evaluated to determine whether a derivative exists and/or whether an instrument may be exempted from derivative accounting if designated as a normal purchase or normal sale. See Note 8 for further information. Commodity Trading Operations — All applicable gains and losses related to commodity trading activities are shown on a net basis in electric operating revenues in the consolidated statements of income. Commodity trading activities are not associated with energy produced from PSCo’s generation assets or energy and capacity purchased to serve native load. Commodity trading contracts are recorded at fair market value and commodity trading results include the impact of all margin-sharing mechanisms. See Note 8 for further information Other Utility Items AFUDC — AFUDC represents the cost of capital used to finance utility construction activity. AFUDC is computed by applying a composite financing rate to qualified CWIP. The amount of AFUDC capitalized as a utility construction cost is credited to other nonoperating income (for equity capital) and interest charges (for debt capital). AFUDC amounts capitalized are included in PSCo’s rate base for establishing utility rates. Alternative Revenue — Certain rate rider mechanisms (including decoupling and DSM programs) qualify as alternative revenue programs. These mechanisms arise from costs imposed upon the utility by action of a regulator or legislative body related to an environmental, public safety or other mandate or from other instances where the regulator authorizes a future surcharge in response to past activities or completed events. When certain criteria are met, including expected collection within 24 months, revenue is recognized equal to the revenue requirement, which may include incentives and return on rate base items. Billing amounts are revised periodically for differences between total amount collected and revenue earned, which may increase or decrease the level of revenue collected from customers. Alternative revenues arising from these programs are presented on a gross basis and disclosed separately from revenue from contracts with customers. See Note 6 for further information. Conservation Programs — PSCo has implemented programs to assist its retail customers in conserving energy and reducing peak demand on the electric and natural gas systems. These programs include approximately 20 unique DSM products, pilots and services for C&I customers, as well as approximately 23 DSM products, pilots and services for residential and low-income customers. Overall, the DSM portfolio provides rebates and/or incentives for nearly 1,000 unique measures. The costs incurred for DSM programs are deferred if it is probable future revenue will be provided to permit recovery of the incurred cost. Revenues recognized for incentive programs designed for recovery of DSM program costs and/or conservation performance incentives are limited to amounts expected to be collected within 24 months from the annual period in which they are earned. PSCo’s DSM program costs are recovered through a combination of base rate revenue and rider mechanisms. Regulatory assets are recognized to reflect the amount of costs or earned incentives that have not yet been collected from customers. Emission Allowances — Emission allowances are recorded at cost, including broker commission fees. The inventory accounting model is utilized for all emission allowances and sales of these allowances are included in electric revenues. RECs — Cost of RECs that are utilized for compliance is recorded as electric fuel and purchased power expense. PSCo reduces recoverable fuel and purchased power costs for the cost of RECs received. An inventory accounting model is used to account for RECs recognized on the consolidated balance sheets, however these assets are classified as regulatory assets if amounts are recoverable in future rates. Sales of RECs are recorded in electric revenues on a gross basis. Cost of these RECs and amounts credited to customers under margin-sharing mechanisms are recorded in electric fuel and purchased power expense.

Property Plant and Equipment Pr

Property Plant and Equipment Property Plant and Equipment	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure	Major classes of property, plant and equipment (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 Property, plant and equipment, net Electric plant $ 16,543 $ 15,736 Natural gas plant 5,471 5,037 Common and other property 1,224 1,191 Plant to be retired (a) 182 225 CWIP 681 510 Total property, plant and equipment 24,101 22,699 Less accumulated depreciation (5,657) (5,229) Property, plant and equipment, net $ 18,444 $ 17,470 (a) Includes regulator-approved retirements of Comanche Units 1 and 2 and jointly owned Craig Unit 1. Also includes PSCo’s planned retirement of jointly owned Craig Unit 2. Joint Ownership of Generation, Transmission and Gas Facilities Jointly owned assets as of Dec. 31, 2021: (Millions of Dollars, Except Percent Owned) Plant in Service Accumulated Depreciation Percent Owned Electric generation: Hayden Unit 1 $ 156 $ 99 76 % Hayden Unit 2 151 78 37 Hayden common facilities 42 27 53 Craig Units 1 and 2 81 48 10 Craig common facilities 39 25 7 Comanche Unit 3 917 154 67 Comanche common facilities 28 2 82 Electric transmission: Transmission and other facilities 182 63 Various Gas transmission: Rifle, CO to Avon, CO 22 8 60 Gas transmission compressor 8 2 50 Total (a) $ 1,626 $ 506 (a) Projects additionally include $3 million in CWIP. PSCo’s share of operating expenses and construction expenditures is included in the applicable utility accounts. Respective owners are responsible for providing their own financing.

Regulatory Assets and Liabiliti

Regulatory Assets and Liabilities	12 Months Ended
	Dec. 31, 2021
Regulatory Assets and Liabilities Disclosure [Abstract]
Regulatory Assets and Liabilities	Regulatory assets and liabilities are created for amounts that regulators may allow to be collected or may require to be paid back to customers in future electric and natural gas rates. PSCo would be required to recognize the write-off of regulatory assets and liabilities in net income or other comprehensive income if changes in the utility industry no longer allow for the application of regulatory accounting guidance under GAAP. Components of regulatory assets: (Millions of Dollars) See Note(s) Remaining Amortization Period Dec. 31, 2021 Dec. 31, 2020 Regulatory Assets Current Noncurrent Current Noncurrent Pension and retiree medical obligations 9 Various $ 26 $ 331 $ 28 $ 478 Deferred natural gas, electric, steam energy/fuel costs One three 218 320 6 — Depreciation differences One ten 16 173 16 154 Net AROs (a) 1, 10 Various — 154 — 132 Recoverable deferred taxes on AFUDC Plant lives — 116 — 110 Excess deferred taxes — TCJA 7 Various 2 56 3 56 Purchased power contract costs Term of related contract 3 19 3 22 Property tax Various 16 16 16 21 Gas pipeline inspection costs One two — 12 — 9 Conservation programs (b) 1 One two 11 11 11 11 Losses on reacquired debt Term of related debt 1 2 1 3 Contract valuation adjustments (c) 1, 8 Less than one year 3 — 6 — Other Various 57 83 31 63 Total regulatory assets $ 353 $ 1,293 $ 121 $ 1,059 (a) Includes amounts recorded for future recovery of AROs. (b) Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions. (c) Includes the fair value of certain long-term PPAs used to meet energy capacity requirements and valuation adjustments on natural gas commodity purchases. Components of regulatory liabilities: (Millions of Dollars) See Note(s) Remaining Amortization Period Dec. 31, 2021 Dec. 31, 2020 Regulatory Liabilities Current Noncurrent Current Noncurrent Deferred income tax adjustments and TCJA refunds (a) 7 Various $ 2 $ 1,328 $ 5 $ 1,368 Plant removal costs 1, 10 Various — 651 — 615 Effects of regulation on employee benefit costs (b) Various — 216 — 203 Renewable resources and environmental initiatives Various — 91 — 59 ITC deferrals 1 Various — 42 — 40 Revenue decoupling One two 9 41 10 41 Conservation programs (c) 1 Less than one year 34 — 39 — Deferred natural gas, electric, steam energy/fuel costs Less than one year 29 — 17 — Other Various 21 28 29 11 Total regulatory liabilities (d) $ 95 $ 2,397 $ 100 $ 2,337 (a) Includes the revaluation of recoverable/regulated plant accumulated deferred income taxes and revaluation impact of non-plant accumulated deferred income taxes due to the TCJA. (b) Includes regulatory amortization and certain 2018 TCJA benefits approved by the CPUC to offset the prepaid pension asset. (c) Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions. (d) Revenue subject to refund of $2 million for 2021 is included in other current liabilities and none for 2020. At Dec. 31, 2021 and 2020, PSCo’s regulatory assets not earning a return primarily included the unfunded portion of pension and retiree medical obligations and net AROs. In addition, PSCo’s regulatory assets included $639 million and $195 million at Dec. 31, 2021 and 2020, respectively, of past expenditures not earning a return. Amounts are related to Winter Storm Uri costs, funded pension obligations, property taxes, various renewable resources and certain environmental initiatives.

Borrowings and Other Financing

Borrowings and Other Financing Instruments	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Borrowings and Other Financing Instruments	5. Borrowings and Other Financing Instruments Short-Term Borrowings PSCo meets its short-term liquidity requirements primarily through the issuance of commercial paper and borrowings under its credit facility and the money pool. Money Pool — Xcel Energy Inc. and its utility subsidiaries have established a money pool arrangement that allows for short-term investments in and borrowings between the utility subsidiaries. Xcel Energy Inc. may make investments in the utility subsidiaries at market-based interest rates; however, the money pool arrangement does not allow the utility subsidiaries to make investments in Xcel Energy Inc. Money pool borrowings: (Millions of Dollars, Except Interest Rates) Three Months Ended Dec. 31, 2021 Year Ended Dec. 31 2021 2020 2019 Borrowing limit $ 250 $ 250 $ 250 $ 250 Amount outstanding at period end — — 57 39 Average amount outstanding 14 12 59 7 Maximum amount outstanding 74 243 250 50 Weighted average interest rate, computed on a daily basis 0.05 % 0.07 % 0.60 % 2.29 % Weighted average interest rate at end of period N/A N/A 0.70 1.63 Commercial Paper — Commercial paper borrowings: (Millions of Dollars, Except Interest Rates) Three Months Ended Dec. 31, 2021 Year Ended Dec. 31 2021 2020 2019 Borrowing limit $ 700 $ 700 $ 700 $ 700 Amount outstanding at period end 147 147 136 — Average amount outstanding 6 26 30 154 Maximum amount outstanding 150 322 230 432 Weighted average interest rate, computed on a daily basis 0.21 % 0.19 % 1.59 % 2.67 % Weighted average interest rate at end of period 0.22 0.22 0.20 N/A Letters of Credit — PSCo uses letters of credit, typically with terms of one year, to provide financial guarantees for certain operating obligations. At Dec. 31, 2021 and 2020, there were $8 million of letters of credit outstanding under the credit facility, respectively. The contract amounts of these letters of credit approximate their fair value and are subject to fees. Credit Facility — In order to use its commercial paper program to fulfill short-term funding needs, PSCo must have a revolving credit facility in place at least equal to the amount of its commercial paper borrowing limit and cannot issue commercial paper in an aggregate amount exceeding available capacity under this credit facility. The credit facility provides short-term financing in the form of notes payable to banks, letters of credit and back-up support for commercial paper borrowings. Features of PSCo’s credit facility: Debt-to-Total Capitalization Ratio (a) Amount Facility May Be Increased (millions of dollars) Additional Periods for Which a One-Year Extension May Be Requested (b) 2021 2020 44 % 44 % $ 100 2 (a) The credit facility has a financial covenant requiring that the debt-to-total capitalization ratio be less than or equal to 65%. (b) All extension requests are subject to majority bank group approval. The credit facility has a cross-default provision that provides PSCo would be in default on its borrowings under the facility if PSCo or any of its subsidiaries whose total assets exceed 15% of PSCo’s consolidated total assets, default on indebtedness in an aggregate principal amount exceeding $75 million . If PSCo does not comply with the covenant, an event of default may be declared, and if not remedied, any outs tanding amounts due under the facility can be declared due by the lender. As of Dec. 31, 2021, PSCo was in compliance with all financial covenants. PSCo had the following committed credit facility available as of Dec. 31, 2021 (in millions of dollars): Credit Facility (a) Drawn (b) Available $ 700 $ 155 $ 545 (a) This credit facility matures in June 2024. (b) Includes letters of credit and outstanding commercial paper. All credit facility bank borrowings, outstanding letters of credit and outstanding commercial paper reduce the available capacity under the credit facility. PSCo had no direct advances on the facility outstanding at Dec. 31, 2021 and 2020. Long-Term Borrowings and Other Financing Instruments Generally, all property of PSCo is subject to the lien of its first mortgage indenture. Debt premiums, discounts and expenses are amortized over the life of the related debt. The premiums, discounts and expenses for refinanced debt are deferred and amortized over the life of the new issuance. Long-term debt obligations for PSCo as of Dec. 31 (in millions of dollars): Financing Instrument Interest Rate Maturity Date 2021 2020 First mortgage bonds 2.25 % Sept. 15, 2022 $ 300 $ 300 First mortgage bonds 2.50 March 15, 2023 250 250 First mortgage bonds 2.90 May 15, 2025 250 250 First mortgage bonds 3.70 June 15, 2028 350 350 First mortgage bonds (b) 1.90 Jan. 15, 2031 375 375 First mortgage bonds (a) 1.875 June 15, 2031 750 — First mortgage bonds 6.25 Sept. 1, 2037 350 350 First mortgage bonds 6.50 Aug. 1, 2038 300 300 First mortgage bonds 4.75 Aug. 15, 2041 250 250 First mortgage bonds 3.60 Sept. 15, 2042 500 500 First mortgage bonds 3.95 March 15, 2043 250 250 First mortgage bonds 4.30 March 15, 2044 300 300 First mortgage bonds 3.55 June 15, 2046 250 250 First mortgage bonds 3.80 June 15, 2047 400 400 First mortgage bonds 4.10 June 15, 2048 350 350 First mortgage bonds 4.05 Sept. 15, 2049 400 400 First mortgage bonds 3.20 March 1, 2050 550 550 First mortgage bonds (b) 2.70 Jan. 15, 2051 375 375 Unamortized discount (33) (30) Unamortized debt issuance cost (50) (46) Current maturities (300) — Total long-term debt $ 6,167 $ 5,724 (a) 2021 financing. (b) 2020 financing. Maturities of long-term debt: (Millions of Dollars) 2022 $ 300 2023 250 2024 — 2025 250 2026 — Deferred Financing Costs — Deferred financing costs of approximately $50 million and $46 million, net of amortization, are presented as a deduction from the carrying amount of long-term debt as of Dec. 31, 2021 and 2020, respectively. PSCo is amortizing these financing costs over the remaining maturity periods of the related debt. Capital Stock — PSCo has authorized the issuance of preferred stock. Preferred Stock Authorized (Shares) Par Value of Preferred Stock Preferred Stock Outstanding (Shares) 2021 and 2020 10,000,000 $ 0.01 — Dividend Restrictions — PSCo’s dividends are subject to the FERC’s jurisdiction, which prohibits the payment of dividends out of capital accounts. Dividends are solely to be paid from retained earnings.

Revenues

Revenues	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenues	Revenue is classified by the type of goods/services rendered and market/customer type. PSCo’s operating revenues consisted of the following: Year Ended Dec. 31, 2021 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 1,174 $ 816 $ 12 $ 2,002 C&I 1,660 308 30 1,998 Other 49 — — 49 Total retail 2,883 1,124 42 4,049 Wholesale 228 — — 228 Transmission 75 — — 75 Other 44 159 — 203 Total revenue from contracts with customers 3,230 1,283 42 4,555 Alternative revenue and other 183 72 5 260 Total revenues $ 3,413 $ 1,355 $ 47 $ 4,815 Year Ended Dec. 31, 2020 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 1,073 $ 650 $ 12 $ 1,735 C&I 1,512 225 27 1,764 Other 48 — — 48 Total retail 2,633 875 39 3,547 Wholesale 212 — — 212 Transmission 62 — — 62 Other 56 125 — 181 Total revenue from contracts with customers 2,963 1,000 39 4,002 Alternative revenue and other 153 24 4 181 Total revenues $ 3,116 $ 1,024 $ 43 $ 4,183 Year Ended Dec. 31, 2019 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 1,006 $ 750 $ 11 $ 1,767 C&I 1,579 281 28 1,888 Other 50 — — 50 Total retail 2,635 1,031 39 3,705 Wholesale 166 — — 166 Transmission 52 — — 52 Other 32 107 — 139 Total revenue from contracts with customers 2,885 1,138 39 4,062 Alternative revenue and other 148 23 4 175 Total revenues $ 3,033 $ 1,161 $ 43 $ 4,237

Income Taxes Income Taxes

Income Taxes Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Federal Tax Loss Carryback Claims — In 2020, Xcel Energy identified certain expenses related to tax years 2009 - 2011 that qualify for an extended carryback claim. PSCo is not expected to accrue any income tax expense related to this adjustment. Federal Audit — PSCo is a member of Xcel Energy affiliated group that files a consolidated federal income tax return. The statute of limitations applicable to Xcel Energy’s consolidated federal tax returns expire as follows: Tax Year(s) Expiration 2014 - 2016 December 2022 2018 September 2022 Additionally, the statute of limitations related to certain federal tax credit carryforwards will remain open until those credits are utilized in subsequent returns. Further, the statute of limitations related to the additional federal tax loss carryback claim filed in 2020 has been extended. Xcel Energy has recognized its best estimate of income tax expense that will result from a final resolution of this issue; however, the outcome and timing of a resolution is unknown. State Audits — PSCo is a member of the Xcel Energy affiliated group that files consolidated state income tax returns. As of Dec. 31, 2021, PSCo’s earliest open tax year that is subject to examination by state taxing authorities under applicable statutes of limitations is 2014. There are currently no state income tax audits in progress. Unrecognized Tax Benefits — Unrecognized tax benefit balance includes permanent tax positions, which if recognized would affect the ETR. In addition, the unrecognized tax benefit balance includes temporary tax positions for which deductibility is highly certain, but for which there is uncertainty about the timing. A change in the timing of deductibility would not affect the ETR but would accelerate the payment to the taxing authority. Unrecognized tax benefits - permanent vs temporary: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 Unrecognized tax benefit — Permanent tax positions $ 9 $ 7 Unrecognized tax benefit — Temporary tax positions 2 2 Total unrecognized tax benefit $ 11 $ 9 Changes in unrecognized tax benefits: (Millions of Dollars) 2021 2020 2019 Balance at Jan. 1 $ 9 $ 12 $ 10 Additions based on tax positions related to the current year 2 2 1 Additions for tax positions of prior years — 6 1 Reductions for tax positions of prior years — (11) — Balance at Dec. 31 $ 11 $ 9 $ 12 Unrecognized tax benefits were reduced by tax benefits associated with NOL and tax credit carryforwards: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 NOL and tax credit carryforwards $ (11) $ (8) As the IRS progresses its review of the tax loss carryback claims and as state audits resume, it is reasonably possible that the amount of unrecognized tax benefit could decrease up to approximately $2 million in the next 12 months. Payable for interest related to unrecognized tax benefits is partially offset by the interest benefit associated with NOL and tax credit carryforwards. Interest payable related to unrecognized tax benefits: (Millions of Dollars) 2021 2020 2019 Payable for interest related to unrecognized tax benefits at Jan. 1 $ — $ (1) $ (1) Interest income related to unrecognized tax benefits — 1 — Payable for interest related to unrecognized tax benefits at Dec. 31 $ — $ — $ (1) No amounts were accrued for penalties related to unrecognized tax benefits as of Dec. 31, 2021, 2020 or 2019. Other Income Tax Matters — NOL amounts represent the tax loss that is carried forward and tax credits represent the deferred tax asset. NOL and tax credit carryforwards as of Dec. 31 were as follows: (Millions of Dollars) 2021 2020 Federal NOL carryforward $ 161 $ — Federal tax credit carryforwards 259 143 State NOL carryforwards 342 190 State tax credit carryforwards, net of federal detriment (a) 17 18 Valuation allowances for state credit carryforwards, net of federal benefit (b) (8) (8) (a) State tax credit carryforwards are net of federal detriment of $5 million as of Dec. 31, 2021 and 2020. (b) Valuation allowances for state tax credit carryforwards were net of federal benefit of $2 million as of Dec. 31, 2021 and 2020. Federal carryforward periods expire between 2031 and 2041 and state carryforward periods expire between 2022 and 2041. Total income tax expense from operations differs from the amount computed by applying the statutory federal income tax rate to income before income tax expense. Effective income tax rate for years ended Dec. 31: 2021 2020 (a) 2019 (a) Federal statutory rate 21.0 % 21.0 % 21.0 % State income tax on pretax income, net of federal tax effect 3.6 3.6 3.6 Increases (decreases) in tax from: Wind PTCs (14.3) (10.3) (7.5) Plant regulatory differences (b) (4.6) (5.0) (3.3) Other tax credits, net NOL & tax credit allowances (1.0) (1.1) (1.3) Change in unrecognized tax benefits 0.3 (0.2) 0.3 Other, net (0.2) (0.9) (0.6) Effective income tax rate 4.8 % 7.1 % 12.2 % (a) Prior periods have been reclassified to conform to current year presentation. (b) Regulatory differences for income tax primarily relate to the credit of excess deferred taxes to customers through the average rate assumption method. Income tax benefits associated with the credit of excess deferred credits are offset by corresponding revenue reductions and additional prepaid pension asset amortization. Components of income tax expense for the years ended Dec. 31: (Millions of Dollars) 2021 2020 2019 Current federal tax expense (benefit) $ 16 $ 44 $ (9) Current state tax expense (benefit) — 4 (5) Current change in unrecognized tax benefit (1) (3) (1) Deferred federal tax (benefit) expense (13) (26) 61 Deferred state tax expense 31 26 33 Deferred change in unrecognized tax expense 3 2 3 Deferred ITCs (3) (2) (2) Total income tax expense $ 33 $ 45 $ 80 Components of deferred income tax expense as of Dec. 31: (Millions of Dollars) 2021 2020 2019 Deferred tax expense excluding items below $ 63 $ 46 $ 132 Amortization and adjustments to deferred income taxes on income tax regulatory assets and liabilities (42) (43) (35) Tax expense allocated to other comprehensive income, adoption of ASC Topic 326, and other — (1) — Deferred tax expense $ 21 $ 2 $ 97 Components of the net deferred tax liability as of Dec. 31: (Millions of Dollars) 2021 2020 (a) Deferred tax liabilities: Differences between book and tax bases of property $ 2,226 $ 2,132 Regulatory assets 258 257 Deferred fuel costs 126 (3) Operating lease assets 106 129 Pension expense and other employee benefits 23 19 Other 7 6 Total deferred tax liabilities $ 2,746 $ 2,540 Deferred tax assets: Regulatory liabilities $ 323 $ 319 Tax credit carryforward 276 161 Operating lease liabilities 106 129 Bad debts 10 8 NOL carryforward 46 7 Deferred ITCs 8 5 Tax credit valuation allowances (8) (8) Other 25 22 Total deferred tax assets $ 786 $ 643 Net deferred tax liability $ 1,960 $ 1,897 (a) Prior periods have been reclassified to conform to current year presentation.

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities	Fair Value Measurements Accounting guidance for fair value measurements and disclosures provides a single definition of fair value and requires disclosures about assets and liabilities measured at fair value. A hierarchical framework for disclosing the observability of the inputs utilized in measuring assets and liabilities at fair value is established by this guidance. • Level 1 — Quoted prices are available in active markets for identical assets or liabilities as of the reporting date. The types of assets and liabilities included in Level 1 are highly liquid and actively traded instruments with quoted prices. • Level 2 — Pricing inputs are other than quoted prices in active markets but are either directly or indirectly observable as of the reporting date. The types of assets and liabilities included in Level 2 are typically either comparable to actively traded securities or contracts or priced with models using highly observable inputs. • Level 3 — Significant inputs to pricing have little or no observability as of the reporting date. The types of assets and liabilities included in Level 3 are those valued with models requiring significant management judgment or estimation. Specific valuation methods include: Cash equivalents — The fair values of cash equivalents are generally based on cost plus accrued interest; money market funds are measured using quoted NAV. Interest rate derivatives — The fair values of interest rate derivatives are based on broker quotes that utilize current market interest rate forecasts. Commodity derivatives — The methods used to measure the fair value of commodity derivative forwards and options utilize forward prices and volatilities, as well as pricing adjustments for specific delivery locations, and are generally assigned a Level 2 classification. When contractual settlements relate to inactive delivery locations or extend to periods beyond those readily observable on active exchanges or quoted by brokers, the significance of the use of less observable forecasts of forward prices and volatilities on a valuation is evaluated and may result in Level 3 classification. Derivative Instruments Fair Value Measurements PSCo enters into derivative instruments, including forward contracts, futures, swaps and options, for trading purposes and to manage risk in connection with changes in interest rates, utility commodity prices and vehicle fuel prices. Interest Rate Derivatives — PSCo enters into various instruments that effectively fix the yield or price on a specified benchmark interest rate for an anticipated debt issuance for a specific period. These derivative instruments are generally designated as cash flow hedges for accounting purposes, with changes in fair value prior to settlement recorded as other comprehensive income. As of Dec. 31, 2021, accumulated other comprehensive loss related to settled interest rate derivatives included $1 million of net losses expected to be reclassified into earnings during the next 12 months as the hedged transactions impact earnings. As of Dec. 31, 2021, PSCo had no unsettled interest rate derivatives. Wholesale and Commodity Trading Risk — PSCo conducts various wholesale and commodity trading activities, including the purchase and sale of electric capacity, energy, energy-related instruments and natural gas-related instruments, including derivatives. PSCo is allowed to conduct these activities within guidelines and limitations as approved by its risk management committee, comprised of management personnel not directly involved in activities governed by this policy. Commodity Derivatives — PSCo enters into derivative instruments to manage variability of future cash flows from changes in commodity prices in its electric and natural gas operations, as well as for trading purposes. This could include the purchase or sale of energy or energy-related products, natural gas to generate electric energy, natural gas for resale, and vehicle fuel. PSCo enters into derivative instruments that mitigate commodity price risk on behalf of electric and natural gas customers but may not be designated as qualifying hedging transactions. The classification of unrealized losses or gains on these instruments as a regulatory asset or liability, if applicable, is based on approved regulatory recovery mechanisms. As of Dec. 31, 2021, PSCo had no commodity contracts designated as cash flow hedges. PSCo enters into commodity derivative instruments for trading purposes not directly related to commodity price risks associated with serving its electric and natural gas customers. Changes in the fair value of these commodity derivatives are recorded in electric operating revenues, net of amounts credited to customers under margin-sharing mechanisms. Gross notional amounts of commodity forwards and options: (Amounts in Millions) (a)(b) Dec. 31, 2021 Dec. 31, 2020 MWh of electricity 15 17 MMBtu of natural gas 71 93 (a) Not reflective of net positions in the underlying commodities. (b) Notional amounts for options included on a gross basis, but are weighted for the probability of exercise. Consideration of Credit Risk and Concentrations — PSCo continuously monitors the creditworthiness of the counterparties to its interest rate derivatives and commodity derivative contracts prior to settlement and assesses each counterparty’s ability to perform on the transactions set forth in the contracts. The impact of credit risk was immaterial to the fair value of unsettled commodity derivatives presented on the consolidated balance sheets. PSCo’s most significant concentrations of credit risk with particular entities or industries are contracts with counterparties to its wholesale, trading and non-trading commodity activities. At Dec. 31, 2021, four of PSCo’s 10 most significant counterparties for these activities, comprising $53 million or 40% of this credit exposure, had investment grade credit ratings from S&P, Moody’s or Fitch Ratings. Five of the 10 most significant counterparties, comprising $20 million or 15% of this credit exposure, were not rated by these external agencies, but based on PSCo’s internal analysis, had credit quality consistent with investment grade. One of these significant counterparties, comprising $38 million, or 29%, of this credit exposure, had credit quality less than investment grade, based on external and internal analysis. Seven of these significant counterparties are independent system operators, municipal, cooperative electric entities, RTOs or other utilities. Qualifying Cash Flow Hedges — Financial impact of qualifying interest rate and vehicle fuel cash flow hedges on PSCo’s accumulated other comprehensive loss, included in the consolidated statements of common stockholder’s equity and in the consolidated statements of comprehensive income: (Millions of Dollars) 2021 2020 2019 Accumulated other comprehensive loss related to cash flow hedges at Jan. 1 $ (23) $ (24) $ (26) After-tax net realized losses on derivative transactions reclassified into earnings 2 1 2 Accumulated other comprehensive loss related to cash flow hedges at Dec. 31 $ (21) $ (23) $ (24) Impact of derivative activity: Pre-Tax Fair Value Gains (Losses) Recognized During the Period in: (Millions of Dollars) Accumulated Other Regulatory (Assets) and Liabilities Year Ended Dec. 31, 2021 Other derivative instruments Natural gas commodity $ — $ (1) Total $ — $ (1) Year Ended Dec. 31, 2020 Other derivative instruments Natural gas commodity $ — $ (10) Total $ — $ (10) Year Ended Dec. 31, 2019 Other derivative instruments Natural gas commodity $ — $ (5) Total $ — $ (5) Pre-Tax (Gains) Losses (Millions of Dollars) Accumulated Loss Regulatory (Liabilities) Pre-Tax Gains (Losses) Recognized Year Ended Dec. 31, 2021 Derivatives designated as cash flow hedges Interest rate $ 2 (a) $ — $ — Total $ 2 $ — $ — Other derivative instruments Commodity trading $ — $ — $ 12 (b) Natural gas commodity — 4 (c) (15) (c) Total $ — $ 4 $ (3) Pre-Tax (Gains) Losses (Millions of Dollars) Accumulated Loss Regulatory (Liabilities) Pre-Tax Gains (Losses) Recognized Year Ended Dec. 31, 2020 Derivatives designated as cash flow hedges Interest rate $ 1 (a) $ — $ — Total $ 1 $ — $ — Other derivative instruments Commodity trading $ — $ — $ 3 (b) Natural gas commodity — 8 (c) (8) (c) Total $ — $ 8 $ (5) Pre-Tax (Gains) Losses (Millions of Dollars) Accumulated Loss Regulatory (Liabilities) Pre-Tax Gains (Losses) Recognized Year Ended Dec. 31, 2019 Derivatives designated as cash flow hedges Interest rate $ 2 (a) $ — $ — Total $ 2 $ — $ — Other derivative instruments Commodity trading $ — $ — $ 3 (b) Natural gas commodity — 1 (c) (4) (c) Total $ — $ 1 $ (1) (a) Recorded to interest charges. (b) Recorded to electric operating revenues. Portions of these gains and losses are subject to sharing with electric customers through margin-sharing mechanisms and deducted from gross revenue, as appropriate. (c) Settlement losses related to natural gas operations are recorded to cost of natural gas sold and transported. These losses are subject to cost-recovery mechanisms and reclassified out of income to a regulatory asset, as appropriate. PSCo had no derivative instruments designated as fair value hedges during the years ended Dec. 31, 2021, 2020 and 2019. Credit Related Contingent Features — Contract provisions for derivative instruments that PSCo enters into, including those accounted for as normal purchase-normal sale contracts and therefore not reflected on the consolidated balance sheets, may require the posting of collateral or settlement of the contracts for various reasons, including if PSCo’s credit ratings are downgraded below its investment grade credit rating by any of the major credit rating agencies. At Dec. 31, 2021 and 2020, there were no derivative instruments in a liability position with such underlying contract provisions. Certain contracts also contain cross default provisions that may require the posting of collateral or settlement of the contracts if there was a failure under the other financing arrangements related to payment terms or other covenants. As of Dec. 31, 2021 and 2020, there were approximately $16 million and $46 million of derivative instruments in a liability position with such underlying contract provisions, respectively. Certain derivative instruments are also subject to contract provisions that contain adequate assurance clauses. These provisions allow counterparties to seek performance assurance, including cash collateral, in the event that PSCo’s ability to fulfill its contractual obligations is reasonably expected to be impaired. PSCo had no collateral posted related to adequate assurance clauses in derivative contracts as of Dec. 31, 2021 and 2020. Recurring Fair Value Measurements — PSCo’s derivative assets and liabilities measured at fair value on a recurring basis were as follows: Dec. 31, 2021 Dec. 31, 2020 Fair Value Fair Value Total Netting (a) Total Fair Value Fair Value Total Netting (a) Total (Millions of Dollars) Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Current derivative assets Other derivative instruments: Commodity trading $ 12 $ 97 $ — $ 109 $ (81) $ 28 $ 1 $ 41 $ 1 $ 43 $ (28) $ 15 Natural gas commodity — 11 — 11 — 11 — 6 — 6 — 6 Total current derivative assets $ 12 $ 108 $ — $ 120 $ (81) $ 39 $ 1 $ 47 $ 1 $ 49 $ (28) $ 21 Noncurrent derivative assets Other derivative instruments: Commodity trading $ 10 $ 28 $ 54 $ 92 $ (65) $ 27 $ 1 $ 27 $ 8 $ 36 $ (20) $ 16 Total noncurrent derivative assets $ 10 $ 28 $ 54 $ 92 $ (65) 27 $ 1 $ 27 $ 8 $ 36 $ (20) $ 16 Current derivative liabilities Other derivative instruments: Commodity trading $ 6 $ 90 $ 16 $ 112 $ (85) $ 27 $ 1 $ 46 $ 7 $ 54 $ (33) $ 21 Natural gas commodity — 3 — 3 — 3 — 6 — 6 — 6 Total current derivative liabilities $ 6 $ 93 $ 16 $ 115 $ (85) $ 30 $ 1 $ 52 $ 7 $ 60 $ (33) $ 27 Noncurrent derivative liabilities Other derivative instruments: Commodity trading $ 3 $ — $ 101 $ 104 $ (75) $ 29 $ 1 $ 24 $ 46 $ 71 $ (20) $ 51 Total noncurrent derivative liabilities $ 3 $ — $ 101 $ 104 $ (75) $ 29 $ 1 $ 24 $ 46 $ 71 $ (20) $ 51 (a) PSCo nets derivative instruments and related collateral on its consolidated balance sheet when supported by a legally enforceable master netting agreement, and all derivative instruments and related collateral amounts were subject to master netting agreements at Dec. 31, 2021 and 2020. At Dec. 31, 2021 and 2020, derivative assets and liabilities include no obligations to return cash collateral, respectively. At Dec. 31, 2021 and 2020, derivative assets and liabilities include rights to reclaim cash collateral of $14 million and $5 million, respectively. The counterparty netting amounts presented exclude settlement receivables and payables and non-derivative amounts that may be subject to the same master netting agreements. Changes in Level 3 commodity derivatives for the years ended Dec. 31, 2021, 2020 and 2019: Year Ended Dec. 31 (Millions of Dollars) 2021 2020 2019 Balance at Jan. 1 $ (44) $ (13) $ — Settlements 4 — (2) Net transactions recorded during the period: Losses recognized in earnings (a) (23) (31) (11) Balance at Dec. 31 $ (63) $ (44) $ (13) (a) Level 3 losses recognized in earnings are subject to offsetting gains of derivative instruments categorized as levels 1 and 2 in the income statement. PSCo recognizes transfers between levels as of the beginning of each period. There were no transfers of amounts between levels for derivative instruments for the years ended Dec. 31, 2021, 2020 and 2019. Fair Value of Long-Term Debt As of Dec. 31, other financial instruments for which the carrying amount did not equal fair value: 2021 2020 (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt, including current portion $ 6,467 $ 7,291 $ 5,724 $ 7,040 Fair value of PSCo’s long-term debt is estimated based on recent trades and observable spreads from benchmark interest rates for similar securities. Fair value estimates are based on information available to management as of Dec. 31, 2021 and 2020, and given the observability of the inputs, fair values presented for long-term debt were assigned as Level 2.

Benefit Plans and Other Postret

Benefit Plans and Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
Benefit Plans and Other Postretirement Benefits	9. Benefit Plans and Other Postretirement Benefits Pension and Postretirement Health Care Benefits Xcel Energy, which includes PSCo, has several noncontributory, qualified, defined benefit pension plans that cover almost all employees. All newly hired or rehired employees participate under the Cash Balance formula, which is based on pay credits using a percentage of annual eligible pay and annual interest credits. The average annual interest crediting rates for these plans was 2.26, 2.24 and 3.11 percent in 2021, 2020, and 2019, respectively. Some employees may participate under legacy formulas such as the traditional final average pay or pension equity. Xcel Energy’s policy is to fully fund into an external trust the actuarially determined pension costs recognized for ratemaking and financial reporting purposes, subject to the limitations of applicable employee benefit and tax laws. In addition to the qualified pension plans, Xcel Energy maintains a SERP and a nonqualified pension plan. The SERP is maintained for certain executives who participated in the plan in 2008, when the SERP was closed to new participants. The nonqualified pension plan provides benefits for compensation that is in excess of the limits applicable to the qualified pension plans, with distributions funded by Xcel Energy’s consolidated operating cash flows. Obligations of the SERP and nonqualified plan as of Dec. 31, 2021 and 2020 were $43 million and $43 million, respectively, of which $2 million was attributable to PSCo in 2021 and 2020, respectively. Xcel Energy recognized net benefit cost for financial reporting for the SERP and nonqualified plans of $4 million in 2021 and $6 million in 2020, respectively, of which immaterial amounts were attributable to PSCo. Xcel Energy, which includes PSCo, investment-return assumption considers the expected long-term performance for each of the asset classes in its pension and postretirement health care portfolio. Xcel Energy considers the historical returns achieved by its asset portfolios over long time periods, as well as long-term projected return levels. 20-years or longer period, as well as the long-term return levels projected and recommended by investment experts. Xcel Energy Inc. and PSCo continually review pension assumptions. Pension cost determination assumes a forecasted mix of investment types over the long-term. • Investment returns in 2021 were above the assumed level of 6.38%. • Investment returns in 2020 were above the assumed level of 6.84%. • Investment returns in 2019 were above the assumed level of 6.84%. • In 2022, PSCo’s expected investment-return assumption is 6.39%. Pension plan and postretirement benefit assets are invested in a portfolio according to Xcel Energy’s return, liquidity and diversification objectives to provide a source of funding for plan obligations and minimize contributions to the plan, within appropriate levels of risk. The principal mechanism for achieving these objectives is the asset allocation given the long-term risk, return, correlation and liquidity characteristics of each particular asset class. There were no significant concentrations of risk in any industry, index, or entity. Market volatility can impact even well-diversified portfolios and significantly affect the return levels achieved by the assets in any year. State agencies also have issued guidelines to the funding of postretirement benefit costs. PSCo is required to fund postretirement benefit costs in irrevocable external trusts that are dedicated to the payment of these postretirement benefits. These assets are invested in a manner consistent with the investment strategy for the pension plan. Xcel Energy’s ongoing investment strategy is based on plan-specific investment recommendations that seek to minimize potential investment and interest rate risk as a plan’s funded status increases over time. The investment recommendations consider many factors and generally result in a greater percentage of long-duration fixed income securities being allocated to specific plans having relatively higher funded status ratios and a greater percentage of growth assets being allocated to plans having relatively lower funded status ratios. Plan Assets For each of the fair value hierarchy levels, PSCo’s pension plan assets measured at fair value: Dec. 31, 2021 (a) Dec. 31, 2020 (a) (Millions of Dollars) Level 1 Level 2 Level 3 Measured at NAV Total Level 1 Level 2 Level 3 Measured at NAV Total Cash equivalents $ 49 $ — $ — $ — $ 49 $ 75 $ — $ — $ — $ 75 Commingled funds 492 — — 409 901 518 — — 388 906 Debt securities — 360 2 — 362 — 270 1 — 271 Equity securities 24 — — — 24 27 — — — 27 Other — 3 — 12 15 2 2 — — 4 Total $ 565 $ 363 $ 2 $ 421 $ 1,351 $ 622 $ 272 $ 1 $ 388 $ 1,283 (a) See Note 8 for further information on fair value measurement inputs and methods. For each of the fair value hierarchy levels, PSCo’s proportionate allocation of the total postretirement benefit plan assets that were measured at fair value: Dec. 31, 2021 (a) Dec. 31, 2020 (a) (Millions of Dollars) Level 1 Level 2 Level 3 Measured at NAV Total Level 1 Level 2 Level 3 Measured at NAV Total Cash equivalents $ 25 $ — $ — $ — $ 25 $ 24 $ — $ — $ — $ 24 Insurance contracts — 46 — — 46 — 45 — — 45 Commingled funds 57 — — 68 125 64 — — 61 125 Debt securities — 194 1 — 195 — 207 — — 207 Other — 2 — — 2 — 3 — — 3 Total $ 82 $ 242 $ 1 $ 68 $ 393 $ 88 $ 255 $ — $ 61 $ 404 (a) See Note 8 for further information on fair value measurement inputs and methods. No assets were transferred in or out of Level 3 for 2021 or 2020. Funded Status — Benefit obligations for both pension and postretirement plans decreased from Dec. 31, 2020 to Dec. 31, 2021, due primarily to benefit payments and increases in discount rates used in actuarial valuations. Comparisons of the actuarially computed benefit obligation, changes in plan assets and funded status of the pension and postretirement health care plans for PSCo are as follows: Pension Benefits Postretirement Benefits (Millions of Dollars) 2021 2020 2021 2020 Change in Benefit Obligation: Obligation at Jan. 1 $ 1,428 $ 1,330 $ 415 $ 380 Service cost 32 30 1 1 Interest cost 39 46 11 13 Plan amendments — — — — Actuarial (gain) loss (57) 102 (31) 52 Plan participants’ contributions — — 7 6 Medicare subsidy reimbursements — — 2 1 Benefit payments (79) (80) (36) (38) Obligation at Dec. 31 $ 1,363 $ 1,428 $ 369 $ 415 Change in Fair Value of Plan Assets: Fair value of plan assets at Jan. 1 $ 1,283 $ 1,124 $ 404 $ 401 Actual return on plan assets 102 189 15 32 Employer contributions 45 50 3 3 Plan participants’ contributions — — 7 6 Benefit payments (79) (80) (36) (38) Fair value of plan assets at Dec. 31 $ 1,351 $ 1,283 $ 393 $ 404 Funded status of plans at Dec. 31 $ (12) $ (145) $ 24 $ (11) Amounts recognized in the Consolidated Balance Sheet at Dec. 31: Noncurrent assets 6 — 24 — Noncurrent liabilities (18) (145) — (11) Net amounts recognized $ (12) $ (145) $ 24 $ (11) Accumulated benefit obligation for the pension plan was $1,291 million and $1,353 million as of Dec. 31, 2021 and 2020, respectively. Pension Benefits Postretirement Benefits Significant Assumptions Used to Measure Benefit Obligations: 2021 2020 2021 2020 Discount rate for year-end valuation 3.08 % 2.71 % 3.09 % 2.65 % Expected average long-term increase in compensation level 3.75 % 3.75 % N/A N/A Mortality table Pri-2012 Pri-2012 Pri-2012 Pri-2012 Health care costs trend rate — initial: Pre-65 N/A N/A 5.30 % 5.50 % Health care costs trend rate — initial: Post-65 N/A N/A 4.90 % 5.00 % Ultimate trend assumption — initial: Pre-65 N/A N/A 4.50 % 4.50 % Ultimate trend assumption — initial: Post-65 N/A N/A 4.50 % 4.50 % Years until ultimate trend is reached N/A N/A 4 5 Net Periodic Benefit Cost (Credit) — Net periodic benefit cost (credit), other than the service cost component, is included in other income (expense) in the statements of income. Components of net periodic benefit cost (credit) and amounts recognized in other comprehensive income and regulatory assets and liabilities: Pension Benefits Postretirement Benefits (Millions of Dollars) 2021 2020 2019 2021 2020 2019 Service cost $ 32 $ 30 $ 26 $ 1 $ — $ 1 Interest cost 39 46 52 11 13 15 Expected return on plan assets (73) (70) (69) (16) (17) (19) Amortization of prior service credit — (3) (3) (4) (4) (5) Amortization of net loss 32 30 25 3 1 3 Settlement charge (a) — — 3 — — — Net periodic pension cost (credit) 30 33 34 (5) (7) (5) Effects of regulation — 4 4 2 3 1 Net benefit cost (credit) recognized for financial reporting $ 30 $ 37 $ 38 $ (3) $ (4) $ (4) Significant Assumptions Used to Measure Costs: Discount rate 2.71 % 3.49 % 4.31 % 2.65 % 3.47 % 4.32 % Expected average long-term increase in compensation level 3.75 3.75 3.75 N/A N/A N/A Expected average long-term rate of return on assets 6.38 6.84 6.84 4.10 4.50 4.50 (a) A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. In 2019, as a result of lump-sum distributions during the plan year, PSCo recorded a total pension settlement ch arge of $3 million. A n immaterial amount was recorded in the income statement in 2019. There were no settlement charges recorded to the qualified pension plans in 2021 or 2020. Pension Benefits Postretirement Benefits (Millions of Dollars) 2021 2020 2021 2020 Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost: Net loss $ 313 $ 432 $ 48 $ 81 Prior service credit (1) (1) (2) (6) Total $ 312 $ 431 $ 46 $ 75 Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates: Current regulatory assets $ 24 $ 25 $ — $ — Noncurrent regulatory assets 288 404 46 75 Deferred income taxes — 1 — — Net-of-tax accumulated other comprehensive income — 1 — — Total $ 312 $ 431 $ 46 $ 75 Measurement date Dec. 31, 2021 Dec. 31, 2020 Dec. 31, 2021 Dec. 31, 2020 Cash Flows — Funding requirements can be impacted by changes to actuarial assumptions, actual asset levels and other calculations prescribed by the requirements of income tax and other pension-related regulations. Required contributions were made in 2019 - 2022 to meet minimum funding requirements. Total voluntary and required pension funding contributions across all four of Xcel Energy’s pension plans were as follows: • $50 million in January 2022, of which $40 million was attributable to PSCo. • $131 million in 2021, of which $46 million was attributable to PSCo. • $150 million in 2020, of which $50 million was attributable to PSCo. • $154 million in 2019, of which $46 million was attributable to PSCo. The postretirement health care plans have no funding requirements other than fulfilling benefit payment obligations when claims are presented and approved. Additional cash funding requirements are prescribed by certain state and federal rate regulatory authorities. Xcel Energy’s voluntary postretirement funding contributions were as follows: • $9 million in January 2022, of which an immaterial amount is attributable to PSCo. • $15 million during 2021, of which $3 million was attributable to PSCo. • $11 million during 2020, of which $3 million was attributable to PSCo. • $15 million during 2019, of which $4 million was attributable to PSCo. Targeted asset allocations: Pension Benefits Postretirement Benefits 2021 2020 2021 2020 Domestic and international equity securities 33 % 35 % 15 % 15 % Long-duration fixed income securities 37 35 — — Short-to-intermediate fixed income securities 11 13 71 72 Alternative investments 17 15 8 9 Cash 2 2 6 4 Total 100 % 100 % 100 % 100 % The asset allocations above reflect target allocations approved in the calendar year to take effect in the subsequent year Plan Amendments — In 2020 and 2019, there were no significant plan amendments made which affected the projected benefit obligation. In 2021, Xcel Energy amended the Xcel Energy Pension Plan and Xcel Energy Inc. Nonbargaining Pension Plan (South) to reduce supplemental benefits for non-bargaining participants as well as to allow the transfer of a portion of non-qualified pension obligations into the qualified plans. Projected Benefit Payments PSCo’s projected benefit payments: (Millions of Dollars) Projected Gross Projected Expected Net Projected 2022 $ 83 $ 30 $ 2 $ 28 2023 82 29 2 27 2024 82 29 2 27 2025 82 28 2 26 2026 81 27 2 25 2027-2031 388 123 13 110 Defined Contribution Plans Xcel Energy, which includes PSCo, maintains 401(k) and other defined contribution plans that cover most employees. Total expense to these plans for PSCo was approximately $12 million in 2021 and 2020 and $11 million in 2019.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	AROs — AROs have been recorded for PSCo’s assets. PSCo’s AROs were as follows: 2021 (Millions Jan. 1, Accretion Cash Flow Revisions (a) Dec. 31, 2021 (b) Electric Steam, hydro and other production $ 137 $ 5 $ 10 $ 152 Wind 40 2 — 42 Distribution 15 1 — 16 Natural gas Transmission and distribution 203 9 (8) 204 Miscellaneous 3 — 5 8 Common Miscellaneous 1 (1) — — Total liability $ 399 $ 16 $ 7 $ 422 (a) In 2021, AROs were revised for changes in timing and estimates of cash flows. Revisions in steam, hydro, and other production AROs primarily related to changes in cost estimates for remediation of ash containment facilities. Changes in gas transmission and distribution AROs were primarily related to changes in labor rates coupled with increased gas line mileage and number of services. (b) There were no ARO amounts incurred or settled in 2021. 2020 (Millions Jan. 1, 2020 Amounts Incurred (a) Amounts Settled (b) Accretion Cash Flow Revisions (c) Dec. 31, 2020 Electric Steam, hydro and other production $ 100 $ — $ — $ 4 $ 33 $ 137 Wind 16 26 (3) 1 — 40 Distribution 14 — — 1 — 15 Natural gas Transmission and distribution 190 — — 8 5 203 Miscellaneous 3 — — — — 3 Common Miscellaneous 1 — — — — 1 Total liability $ 324 $ 26 $ (3) $ 14 $ 38 $ 399 (a) Amounts incurred related to the Cheyenne Ridge wind farm placed in service in 2020. (b) Amounts settled related to removal of wind facilities. (c) In 2020, AROs were revised for changes in timing and estimates of cash flows. Revisions in steam, hydro, and other production AROs primarily related to changes in cost estimates for remediation of ash containment facilities. Indeterminate AROs — Outside of the recorded asbestos AROs, other plants or buildings may contain asbestos due to the age of many of PSCo’s facilities, but no confirmation or measurement of the cost of removal could be determined as of Dec. 31, 2021. Therefore, an ARO has not been recorded for these facilities. Leases PSCo evaluates contracts that may contain leases, including PPAs and arrangements for the use of office space and other facilities, vehicles and equipment. A contract contains a lease if it conveys the exclusive right to control the use of a specific asset. A contract determined to contain a lease is evaluated further to determine if the arrangement is a finance lease. ROU assets represent PSCo's rights to use leased assets. The present value of future operating lease payments is recognized in current and noncurrent operating lease liabilities. These amounts, adjusted for any prepayments or incentives, are recognized as operating lease ROU assets. Most of PSCo’s leases do not contain a readily determinable discount rate. Therefore, the present value of future lease payments is generally calculated using the estimated incremental borrowing rate (weighted average of 3.9%). PSCo has elected to utilize the practical expedient under which non-lease components, such as asset maintenance costs included in payments, are not deducted from minimum lease payments for the purposes of lease accounting and disclosure. Leases with an initial term of 12 months or less are classified as short-term leases and are not recognized on the consolidated balance sheet. Operating lease ROU assets: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 PPAs $ 600 $ 591 Other 77 68 Gross operating lease ROU assets 677 659 Accumulated amortization (268) (159) Net operating lease ROU assets $ 409 $ 500 ROU assets for finance leases are included in other noncurrent assets, and the present value of future finance lease payments is included in other current liabilities and other noncurrent liabilities. PSCo’s most significant finance lease activities are related to WYCO, a joint venture with CIG, to develop and lease natural gas pipeline, storage and compression facilities. Xcel Energy Inc. has a 50% ownership interest in WYCO. WYCO leases its facilities to CIG, and CIG operates the facilities, providing natural gas storage and transportation services to PSCo under separate service agreements. PSCo accounts for its Totem natural gas storage service and Front Range pipeline arrangements with CIG and WYCO, respectively, as finance leases. Finance lease ROU assets: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 Gas storage facilities $ 201 $ 201 Gas pipeline 21 21 Gross finance lease ROU assets 222 222 Accumulated amortization (97) (90) Net finance lease ROU assets $ 125 $ 132 Components of lease expense: (Millions of Dollars) 2021 2020 2019 Operating leases PPA capacity payments $ 102 $ 100 $ 98 Other operating leases (a) 16 13 14 Total operating lease expense (b) $ 118 $ 113 $ 112 Finance leases Amortization of ROU assets $ 7 $ 7 $ 6 Interest expense on lease liability 17 18 19 Total finance lease expense $ 24 $ 25 $ 25 (a) Includes short-term lease expense of $1 million , $1 million and $2 million for 2021, 2020 and 2019, respectively. (b) PPA capacity payments are included in electric fuel and purchased power on the consolidated statements of income. Expense for other operating leases is included in O&M expense and electric fuel and purchased power. Commitments under operating and finance leases as of Dec. 31, 2021: (Millions of Dollars) PPA (a) (b) Operating Leases Other Operating Leases Total Leases Finance Leases 2022 $ 84 $ 16 $ 100 $ 21 2023 70 11 81 20 2024 63 11 74 20 2025 63 5 68 19 2026 59 1 60 18 Thereafter 104 11 115 362 Total minimum obligation 443 55 498 460 Interest component of obligation (57) (6) (63) (335) Present value of minimum obligation $ 386 $ 49 435 125 Less current portion (84) (4) Noncurrent operating and finance lease liabilities $ 351 $ 121 Weighted-average remaining lease term in years 6.5 37.3 (a) Amounts do not include PPAs accounted for as executory contracts and/or contingent payments, such as energy payments on renewable PPAs. (b) PPA operating leases contractually expire at various dates through 2032. Non-Lease PPAs — SPS has entered into PPAs with other utilities and energy suppliers for purchased power to meet system load and energy requirements, operating reserve obligations and as part of wholesale and commodity trading activities. In general, these agreements provide for energy payments, based on actual energy delivered and capacity payments. Certain PPAs, accounted for as executory contracts with various expiration dates through 2027, contain minimum energy purchase requirements. Included in electric fuel and purchased power expenses for PPAs accounted for as executory contracts were payments for capacity of $2 million, $10 million and $12 million in 2021, 2020 and 2019, respectively. Capacity and energy payments are contingent on the IPP meeting contract obligations, including plant availability requirements. Certain contractual payments are adjusted based on market indices. The effects of price adjustments on financial results are mitigated through purchased energy cost recovery mechanisms. At Dec. 31, 2021, the estimated future payments for capacity that PSCo is obligated to purchase pursuant to these executory contracts, subject to availability, were as follows: (Millions of Dollars) Capacity 2022 $ 3 2023 3 2024 3 2025 3 2026 3 Thereafter 3 Total $ 18 Fuel Contracts — PSCo has entered into various long-term commitments for the purchase and delivery of a significant portion of its coal and natural gas requirements. These contracts expire between 2023 and 2060. PSCo is required to pay additional amounts depending on actual quantities shipped under these agreements. Estimated minimum purchases under these contracts as of Dec. 31, 2021: (Millions of Dollars) Coal Natural gas supply Natural gas storage and 2022 $ 186 $ 324 $ 116 2023 102 75 67 2024 67 3 37 2025 28 — 36 2026 29 — 35 Thereafter 30 — 440 Total $ 442 $ 402 $ 731 VIEs Under certain PPAs, PSCo purchases power from IPPs for which PSCo is required to reimburse fuel costs, or to participate in tolling arrangements under which PSCo procures the natural gas required to produce the energy that it purchases. PSCo has determined that certain IPPs are VIEs. PSCo is not subject to risk of loss from the operations of these entities, and no significant financial support is required other than contractual payments for energy and capacity.

Other Comprehensive Income

Other Comprehensive Income	12 Months Ended
	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
Other Comprehensive Income	Changes in accumulated other comprehensive loss, net of tax, for the years ended Dec. 31: 2021 (Millions of Dollars) Gains and Losses on Cash Flow Hedges Defined Benefit Pension and Postretirement Items Total Accumulated other comprehensive loss at Jan. 1 $ (23) $ (1) $ (24) Losses reclassified from net accumulated other comprehensive loss: Interest rate derivatives (net of taxes of $— and $—, respectively) 1 (a) — 1 Amortization of net actuarial loss (net of taxes of $— and $—, respectively) 1 — (b) 1 Net current period other comprehensive income (loss) 2 — 2 Accumulated other comprehensive loss at Dec. 31 $ (21) $ (1) $ (22) (a) Included in interest charges. (b) Included in the computation of net periodic pension and postretirement benefit costs. See Note 9 for further information. 2020 (Millions of Dollars) Gains and Losses on Cash Flow Hedges Defined Benefit Pension and Postretirement Items Total Accumulated other comprehensive loss at Jan. 1 $ (24) $ (3) $ (27) Losses (gains) reclassified from net accumulated other comprehensive loss: Interest rate derivatives (net of taxes of $— and $—, respectively) 1 (a) — 1 Amortization of net actuarial gains (net of taxes of $— and $1, respectively) — 2 (b) 2 Net current period other comprehensive income 1 2 3 Accumulated other comprehensive loss at Dec. 31 $ (23) $ (1) $ (24) (a) Included in interest charges.

Segments and Related Informatio

Segments and Related Information	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Segment Information	PSCo evaluates performance based on profit or loss generated from the product or service provided. These segments are managed separately because the revenue streams are dependent upon regulated rate recovery, which is separately determined for each segment. PSCo has the following reportable segments: • Regulated Electric — The regulated electric utility segment generates, transmits and distributes electricity in Colorado. This segment includes sales for resale and provides wholesale transmission service to various entities in the United States. The regulated electric utility segment also includes PSCo’s wholesale commodity and trading operations. • Regulated Natural Gas — The regulated natural gas utility segment transports, stores and distributes natural gas in portions of Colorado. PSCo also presents All Other, which includes operating segments with revenues below the necessary quantitative thresholds. Those operating segments primarily include steam revenue, appliance repair services and non-utility real estate activities. Asset and capital expenditure information is not provided for PSCo’s reportable segments because as an integrated electric and natural gas utility, PSCo operates significant assets that are not dedicated to a specific business segment. Reporting assets and capital expenditures by business segment would require arbitrary and potentially misleading allocations, which may not necessarily reflect the assets that would be required for the operation of the business segments on a stand-alone basis. Certain costs, such as common depreciation, common O&M expenses and interest expense are allocated based on cost causation allocators across each segment. In addition, a general allocator is used for certain general and administrative expenses, including office supplies, rent, property insurance and general advertising. PSCo’s segment information: (Millions of Dollars) 2021 2020 2019 Regulated Electric Operating revenues — external $ 3,413 $ 3,116 $ 3,033 Intersegment revenue 1 1 1 Total revenues $ 3,414 $ 3,117 $ 3,034 Depreciation and amortization 566 497 455 Interest charges and financing costs 179 173 173 Income tax (benefit) expense (16) 13 45 Net income 495 460 465 Regulated Natural Gas Total revenues $ 1,355 $ 1,024 $ 1,161 Depreciation and amortization 171 152 141 Interest charges and financing costs 53 50 50 Income tax expense 45 29 33 Net income 168 126 119 All Other Total revenues (a) $ 47 $ 43 $ 43 Depreciation and amortization 7 6 6 Interest charges and financing costs 2 1 1 Income tax expense 4 3 2 Net (loss) income (3) 2 (6) Consolidated Total Total revenues (a) $ 4,816 $ 4,184 $ 4,238 Reconciling eliminations (1) (1) (1) Total operating revenues $ 4,815 $ 4,183 $ 4,237 Depreciation and amortization 744 655 602 Interest charges and financing costs 234 224 224 Income tax expense 33 45 80 Net income 660 588 578 (a) Operating revenues include $5 million of other affiliate revenue for the years ended Dec. 31, 2021, 2020 and 2019, respectively. See Note 13 for further information.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Related Party Transactions	Xcel Energy Services Inc. provides management, administrative and other services for the subsidiaries of Xcel Energy Inc., including PSCo. The services are provided and billed to each subsidiary in accordance with service agreements executed by each subsidiary. PSCo uses services provided by Xcel Energy Services Inc. whenever possible. Costs are charged directly to the subsidiary and are allocated if they cannot be directly assigned. Xcel Energy, Inc., NSP-Minnesota, NSP-Wisconsin, PSCo and SPS have established a utility money pool arrangement. See Note 5 for further information. Significant affiliate transactions among the companies and related parties for the years ended Dec. 31: (Millions of Dollars) 2021 2020 2019 Operating revenues: Other $ 5 $ 5 $ 5 Operating expenses: Other operating expenses — paid to Xcel Energy Services Inc. 617 571 532 Accounts receivable and payable with affiliates at Dec. 31: 2021 2020 (Millions of Dollars) Accounts Receivable Accounts Payable Accounts Receivable Accounts Payable NSP-Minnesota $ — $ 16 $ — $ 1 NSP-Wisconsin — 2 — 1 SPS — 7 — 6 Other subsidiaries of Xcel Energy Inc. 13 44 8 50 $ 13 $ 69 $ 8 $ 58

Summarized Quarterly Financial

Summarized Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Summarized Quarterly Financial Data (Unaudited)	Quarter Ended (Millions of Dollars) March 31, 2021 June 30, 2021 Sept. 30, 2021 Dec. 31, 2021 Operating revenues $ 1,057 $ 911 $ 1,081 $ 1,134 Operating income 196 161 290 176 Net income 129 108 218 133 Quarter Ended (Millions of Dollars) March 31, 2020 June 30, 2020 Sept. 30, 2020 Dec. 31, 2020 Operating revenues $ 1,057 $ 911 $ 1,081 $ 1,134 Operating income 196 161 290 176 Net income 129 108 218 133

Schedule II, Valuation and Qual

Schedule II, Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2021
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II, Valuation and Qualifying Accounts	Public Service Co. of Colorado and Subsidiaries Valuation and Qualifying Accounts Years Ended Dec. 31 Allowance for bad debts (Millions of Dollars) 2021 2020 2019 Balance at Jan. 1 $ 29 $ 21 $ 21 Additions charged to costs and expenses 26 24 17 Additions charged to other accounts (a) 4 4 6 Deductions from reserves (b) (19) (20) (23) Balance at Dec. 31 $ 40 $ 29 $ 21 (a) Recovery of amounts previously written-off. (b) Deductions related primarily to bad debt write-offs.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Business and System of Accounts	General — PSCo is engaged in the regulated generation, purchase, transmission, distribution and sale of electricity and in the regulated purchase, transportation, distribution and sale of natural gas.
Principles of Consolidation	PSCo’s consolidated financial statements include its wholly-owned subsidiaries. In the consolidation process, all intercompany transactions and balances are eliminated. PSCo has investments in several plants and transmission facilities jointly owned with nonaffiliated utilities. PSCo’s proportionate share of jointly owned facilities is recorded as property, plant and equipment on the consolidated balance sheets, and PSCo’s proportionate share of the operating costs associated with these facilities is included in its consolidated statements of income.
Subsequent Events	PSCo has evaluated events occurring after Dec. 31, 2021 up to the date of issuance of these consolidated financial statements. These statements contain all necessary adjustments and disclosures resulting from that evaluation.
Use of Estimates	Use of Estimates — PSCo uses estimates based on the best information available in recording transactions and balances resulting from business operations. Estimates are used for items such as plant depreciable lives or potential disallowances, AROs, certain regulatory assets and liabilities, tax provisions, uncollectible amounts, environmental costs, unbilled revenues, jurisdictional fuel and energy cost allocations and actuarially determined benefit costs. Recorded estimates are revised when better information becomes available or actual amounts can be determined. Revisions can affect operating results.
Regulatory Accounting	Regulatory Accounting — PSCo accounts for income and expense items in accordance with accounting guidance for regulated operations . Under this guidance: • Certain costs, which would otherwise be charged to expense or other comprehensive income, are deferred as regulatory assets based on the expected ability to recover the costs in future rates. • Certain credits, which would otherwise be reflected as income or other comprehensive income, are deferred as regulatory liabilities based on the expectation the amounts will be returned to customers in future rates, or because the amounts were collected in rates prior to the costs being incurred. Estimates of recovering deferred costs and returning deferred credits are based on specific ratemaking decisions or precedent for each item. Regulatory assets and liabilities are amortized consistent with the treatment in the rate setting process. If changes in the regulatory environment occur, PSCo may no longer be eligible to apply this accounting treatment and may be required to eliminate regulatory assets and liabilities from its balance sheet. Such changes could have a material effect on PSCo’s results of operations, financial condition and cash flows.
Income Taxes	Income Taxes — PSCo accounts for income taxes using the asset and liability method, which requires recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. PSCo defers income taxes for all temporary differences between pretax financial and taxable income and between the book and tax bases of assets and liabilities. PSCo uses rates that are scheduled to be in effect when the temporary differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in the period that includes the enactment date. The effects of PSCo’s tax rate changes are generally subject to a normalization method of accounting. Therefore, the revaluation of most of its net deferred taxes upon a tax rate reduction results in the establishment of a net regulatory liability, which would be refundable to utility customers over the remaining life of the related assets. PSCo anticipates that a tax rate increase would result in the establishment of a regulatory asset, subject to an evaluation of whether future recovery is expected. Tax credits are recorded when earned unless there is a requirement to defer the benefit and amortize it over the book depreciable lives of the related property. The requirement to defer and amortize tax credits only applies to federal ITCs related to public utility property. Utility rate regulation also has resulted in the recognition of regulatory assets and liabilities related to income taxes. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax asset will not be realized. PSCo follows the applicable accounting guidance to measure and disclose uncertain tax positions that it has taken or expects to take in its income tax returns. PSCo recognizes a tax position in its consolidated financial statements when it is more likely than not that the position will be sustained upon examination based on the technical merits of the position. Recognition of changes in uncertain tax positions are reflected as a component of income tax expense. PSCo reports interest and penalties related to income taxes within other (expense) income or interest charges in the consolidated statements of income. Xcel Energy Inc. and its subsidiaries, including PSCo, file consolidated federal income tax returns as well as consolidated or separate state income tax returns. Federal income taxes paid by Xcel Energy Inc. are allocated to its subsidiaries based on separate company computations. A similar allocation is made for state income taxes paid by Xcel Energy Inc. in connection with consolidated state filings. Xcel Energy Inc. also allocates its own income tax benefits to its direct subsidiaries. See Note 7 for further information.
Property, Plant and Equipment and Depreciation	Property, Plant and Equipment and Depreciation in Regulated Operations — Property, plant and equipment is stated at original cost. The cost of plant includes direct labor and materials, contracted work, overhead costs and AFUDC. The cost of plant retired is charged to accumulated depreciation and amortization. Amounts recovered in rates for future removal costs are recorded as regulatory liabilities. Significant additions or improvements extending asset lives are capitalized, while repairs and maintenance costs are charged to expense as incurred. Maintenance and replacement of items determined to be less than a unit of property are charged to operating expenses as incurred. Planned maintenance activities are charged to operating expense unless the cost represents the acquisition of an additional unit of property or the replacement of an existing unit of property. Property, plant and equipment is tested for impairment when it is determined that the carrying value of the assets may not be recoverable. A loss is recognized in the current period if it becomes probable that part of a cost of a plant under construction or recently completed plant will be disallowed for recovery from customers and a reasonable estimate of the disallowance can be made. For investments in property, plant and equipment that are abandoned and not expected to go into service, incurred costs and related deferred tax amounts are compared to the discounted estimated future rate recovery, and a loss is recognized, if necessary. PSCo records depreciation expense using the straight-line method over the plant’s commission-approved useful life. Actuarial life studies are performed and submitted to the state and federal commissions for review. Upon acceptance by the various commissions, the resulting lives and net salvage rates are used to calculate depreciation. Plant removal costs are recovered in rates as authorized by the appropriate regulatory entities. The amount of removal costs is based on current factors used in existing depreciation rates. Depreciation expense, expressed as a percentage of average depreciable property, was approximately 3.2% in 2021, 3.1% in 2020 and 2.9% in 2019. See Note 3 for further information.
Asset Retirement Obligations	AROs — PSCo accounts for AROs under accounting guidance that requires a liability for the fair value of an ARO to be recognized in the period in which it is incurred if it can be reasonably estimated, with the offsetting associated asset retirement costs capitalized as a long-lived asset. The liability is generally increased over time by applying the effective interest method of accretion, and the capitalized costs are depreciated over the useful life of the long-lived asset. Changes resulting from revisions to the timing or amount of expected asset retirement cash flows are recognized as an increase or a decrease in the ARO. See Note 10 for further information.
Benefit Plans and Other Postretirement Benefits	Benefit Plans and Other Postretirement Benefits — PSCo maintains pension and postretirement benefit plans for eligible employees. Recognizing the cost of providing benefits and measuring the projected benefit obligation of these plans requires management to make various assumptions and estimates. Certain unrecognized actuarial gains and losses and unrecognized prior service costs or credits are deferred as regulatory assets and liabilities, rather than recorded as other comprehensive income, based on regulatory recovery mechanisms. See Note 9 for further information.
Environmental Costs	Environmental Costs — Environmental costs are recorded when it is probable PSCo is liable for remediation costs and the liability can be reasonably estimated. Costs are deferred as a regulatory asset if it is probable that the costs will be recovered from customers in future rates. Otherwise, the costs are expensed. For certain environmental costs related to facilities currently in use, such as for emission-control equipment, the cost is capitalized and depreciated over the life of the plant. Estimated remediation costs are regularly adjusted as estimates are revised and remediation proceeds. If other participating potentially responsible parties exist and acknowledge their potential involvement with a site, costs are estimated and recorded only for PSCo’s expected share of the cost. Future costs of restoring sites are treated as a capitalized cost of plant retirement. The depreciation expense levels recoverable in rates include a provision for removal expenses. Removal costs recovered in rates before the related costs are incurred are classified as a regulatory liability. See Note 10 for further information.
Revenue From Contracts With Customers	Revenue from Contracts with Customers — Performance obligations related to the sale of energy are satisfied as energy is delivered to customers. PSCo recognizes revenue that corresponds to the price of the energy delivered to the customer. The measurement of energy sales to customers is generally based on the reading of their meters, which occurs systematically throughout the month. At the end of each month, amounts of energy delivered to customers since the date of the last meter reading are estimated, and the corresponding unbilled revenue is recognized. PSCo does not recognize a separate financing component of its collections from customers as contract terms are short-term in nature. PSCo presents its revenues net of any excise or sales taxes or fees. See Note 6 for further information.
Cash and Cash Equivalents	Cash and Cash Equivalents — PSCo considers investments in instruments with a remaining maturity of three months or less at the time of purchase to be cash equivalents.
Accounts Receivable and Allowance for Bad Debts	Accounts Receivable and Allowance for Bad Debts — Accounts receivable are stated at the actual billed amount net of an allowance for bad debts. PSCo establishes an allowance for uncollectible receivables based on a policy that reflects its expected exposure to the credit risk of customers. As of Dec. 31, 2021 and 2020, the allowance for bad debts was $40 million and $29 million, respectively.
Inventory	Inventory — Inventory is recorded at average cost and consisted of the following: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 Inventories Materials and supplies $ 70 $ 63 Fuel 71 73 Natural gas 104 53 Total inventories $ 245 $ 189
Fair Value Measurements	Fair Value Measurements — PSCo presents cash equivalents, interest rate derivatives and commodity derivatives at estimated fair values in its consolidated financial statements. Cash equivalents are recorded at cost plus accrued interest; money market funds are measured using quoted NAVs. For interest rate derivatives, quoted prices based primarily on observable market interest rate curves are used to establish fair value. For commodity derivatives, the most observable inputs available are generally used to determine the fair value of each contract. In the absence of a quoted price, PSCo may use quoted prices for similar contracts or internally prepared valuation models to determine fair value. For the pension and postretirement plan assets, published trading data and pricing models, generally using the most observable inputs available, are utilized to estimate fair value for each security. See Notes 8 and 9 for further information.
Derivative Instruments	Derivative Instruments — PSCo uses derivative instruments in connection with its interest rate, utility commodity price and commodity trading activities, including forward contracts, futures, swaps and options. Any derivative instruments not qualifying for the normal purchases and normal sales exception are recorded on the consolidated balance sheets at fair value as derivative instruments. Classification of changes in fair value for those derivative instruments is dependent on the designation of a qualifying hedging relationship. Changes in fair value of derivative instruments not designated in a qualifying hedging relationship are reflected in current earnings or as a regulatory asset or liability. Classification as a regulatory asset or liability is based on commission approved regulatory recovery mechanisms. Gains or losses on commodity trading transactions are recorded as a component of electric operating revenues and interest rate hedging transactions are recorded as a component of interest expense. Normal Purchases and Normal Sales — PSCo enters into contracts for purchases and sales of commodities for use in its operations. At inception, contracts are evaluated to determine whether a derivative exists and/or whether an instrument may be exempted from derivative accounting if designated as a normal purchase or normal sale. See Note 8 for further information.
Commodity Trading Operations	Commodity Trading Operations — All applicable gains and losses related to commodity trading activities are shown on a net basis in electric operating revenues in the consolidated statements of income. Commodity trading activities are not associated with energy produced from PSCo’s generation assets or energy and capacity purchased to serve native load. Commodity trading contracts are recorded at fair market value and commodity trading results include the impact of all margin-sharing mechanisms. See Note 8 for further information
AFUDC	AFUDC — AFUDC represents the cost of capital used to finance utility construction activity. AFUDC is computed by applying a composite financing rate to qualified CWIP. The amount of AFUDC capitalized as a utility construction cost is credited to other nonoperating income (for equity capital) and interest charges (for debt capital). AFUDC amounts capitalized are included in PSCo’s rate base for establishing utility rates.
Alternative Revenue Programs	Alternative Revenue — Certain rate rider mechanisms (including decoupling and DSM programs) qualify as alternative revenue programs. These mechanisms arise from costs imposed upon the utility by action of a regulator or legislative body related to an environmental, public safety or other mandate or from other instances where the regulator authorizes a future surcharge in response to past activities or completed events. When certain criteria are met, including expected collection within 24 months, revenue is recognized equal to the revenue requirement, which may include incentives and return on rate base items. Billing amounts are revised periodically for differences between total amount collected and revenue earned, which may increase or decrease the level of revenue collected from customers. Alternative revenues arising from these programs are presented on a gross basis and disclosed separately from revenue from contracts with customers. See Note 6 for further information. Conservation Programs — PSCo has implemented programs to assist its retail customers in conserving energy and reducing peak demand on the electric and natural gas systems. These programs include approximately 20 unique DSM products, pilots and services for C&I customers, as well as approximately 23 DSM products, pilots and services for residential and low-income customers. Overall, the DSM portfolio provides rebates and/or incentives for nearly 1,000 unique measures. The costs incurred for DSM programs are deferred if it is probable future revenue will be provided to permit recovery of the incurred cost. Revenues recognized for incentive programs designed for recovery of DSM program costs and/or conservation performance incentives are limited to amounts expected to be collected within 24 months from the annual period in which they are earned. PSCo’s DSM program costs are recovered through a combination of base rate revenue and rider mechanisms. Regulatory assets are recognized to reflect the amount of costs or earned incentives that have not yet been collected from customers.
Emission Allowances	Emission Allowances — Emission allowances are recorded at cost, including broker commission fees. The inventory accounting model is utilized for all emission allowances and sales of these allowances are included in electric revenues.
Renewable Energy Credits	RECs — Cost of RECs that are utilized for compliance is recorded as electric fuel and purchased power expense. PSCo reduces recoverable fuel and purchased power costs for the cost of RECs received. An inventory accounting model is used to account for RECs recognized on the consolidated balance sheets, however these assets are classified as regulatory assets if amounts are recoverable in future rates. Sales of RECs are recorded in electric revenues on a gross basis. Cost of these RECs and amounts credited to customers under margin-sharing mechanisms are recorded in electric fuel and purchased power expense.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies Inventory (Tables)	12 Months Ended
	Dec. 31, 2021
Balance Sheet Related Disclosure - Inventory [Abstract]
Public Utilities, Inventory	Inventory — Inventory is recorded at average cost and consisted of the following: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 Inventories Materials and supplies $ 70 $ 63 Fuel 71 73 Natural gas 104 53 Total inventories $ 245 $ 189

Property Plant and Equipment _2

Property Plant and Equipment Property Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Public Utility Property, Plant, and Equipment	Major classes of property, plant and equipment (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 Property, plant and equipment, net Electric plant $ 16,543 $ 15,736 Natural gas plant 5,471 5,037 Common and other property 1,224 1,191 Plant to be retired (a) 182 225 CWIP 681 510 Total property, plant and equipment 24,101 22,699 Less accumulated depreciation (5,657) (5,229) Property, plant and equipment, net $ 18,444 $ 17,470 (a) Includes regulator-approved retirements of Comanche Units 1 and 2 and jointly owned Craig Unit 1. Also includes PSCo’s planned retirement of jointly owned Craig Unit 2.
Schedule of Jointly Owned Utility Plants	Joint Ownership of Generation, Transmission and Gas Facilities Jointly owned assets as of Dec. 31, 2021: (Millions of Dollars, Except Percent Owned) Plant in Service Accumulated Depreciation Percent Owned Electric generation: Hayden Unit 1 $ 156 $ 99 76 % Hayden Unit 2 151 78 37 Hayden common facilities 42 27 53 Craig Units 1 and 2 81 48 10 Craig common facilities 39 25 7 Comanche Unit 3 917 154 67 Comanche common facilities 28 2 82 Electric transmission: Transmission and other facilities 182 63 Various Gas transmission: Rifle, CO to Avon, CO 22 8 60 Gas transmission compressor 8 2 50 Total (a) $ 1,626 $ 506

Regulatory Assets and Liabili_2

Regulatory Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Regulatory Assets and Liabilities Disclosure [Abstract]
Regulatory Assets	Components of regulatory assets: (Millions of Dollars) See Note(s) Remaining Amortization Period Dec. 31, 2021 Dec. 31, 2020 Regulatory Assets Current Noncurrent Current Noncurrent Pension and retiree medical obligations 9 Various $ 26 $ 331 $ 28 $ 478 Deferred natural gas, electric, steam energy/fuel costs One three 218 320 6 — Depreciation differences One ten 16 173 16 154 Net AROs (a) 1, 10 Various — 154 — 132 Recoverable deferred taxes on AFUDC Plant lives — 116 — 110 Excess deferred taxes — TCJA 7 Various 2 56 3 56 Purchased power contract costs Term of related contract 3 19 3 22 Property tax Various 16 16 16 21 Gas pipeline inspection costs One two — 12 — 9 Conservation programs (b) 1 One two 11 11 11 11 Losses on reacquired debt Term of related debt 1 2 1 3 Contract valuation adjustments (c) 1, 8 Less than one year 3 — 6 — Other Various 57 83 31 63 Total regulatory assets $ 353 $ 1,293 $ 121 $ 1,059 (a) Includes amounts recorded for future recovery of AROs. (b) Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions. (c) Includes the fair value of certain long-term PPAs used to meet energy capacity requirements and valuation adjustments on natural gas commodity purchases.
Regulatory Liabilities	Components of regulatory liabilities: (Millions of Dollars) See Note(s) Remaining Amortization Period Dec. 31, 2021 Dec. 31, 2020 Regulatory Liabilities Current Noncurrent Current Noncurrent Deferred income tax adjustments and TCJA refunds (a) 7 Various $ 2 $ 1,328 $ 5 $ 1,368 Plant removal costs 1, 10 Various — 651 — 615 Effects of regulation on employee benefit costs (b) Various — 216 — 203 Renewable resources and environmental initiatives Various — 91 — 59 ITC deferrals 1 Various — 42 — 40 Revenue decoupling One two 9 41 10 41 Conservation programs (c) 1 Less than one year 34 — 39 — Deferred natural gas, electric, steam energy/fuel costs Less than one year 29 — 17 — Other Various 21 28 29 11 Total regulatory liabilities (d) $ 95 $ 2,397 $ 100 $ 2,337 (a) Includes the revaluation of recoverable/regulated plant accumulated deferred income taxes and revaluation impact of non-plant accumulated deferred income taxes due to the TCJA. (b) Includes regulatory amortization and certain 2018 TCJA benefits approved by the CPUC to offset the prepaid pension asset. (c) Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions. (d) Revenue subject to refund of $2 million for 2021 is included in other current liabilities and none for 2020.

Borrowings and Other Financin_2

Borrowings and Other Financing Instruments (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Money Pool [Table Text Block]	Money pool borrowings: (Millions of Dollars, Except Interest Rates) Three Months Ended Dec. 31, 2021 Year Ended Dec. 31 2021 2020 2019 Borrowing limit $ 250 $ 250 $ 250 $ 250 Amount outstanding at period end — — 57 39 Average amount outstanding 14 12 59 7 Maximum amount outstanding 74 243 250 50 Weighted average interest rate, computed on a daily basis 0.05 % 0.07 % 0.60 % 2.29 % Weighted average interest rate at end of period N/A N/A 0.70 1.63
Schedule of Short-term Debt [Table Text Block]	Commercial paper borrowings: (Millions of Dollars, Except Interest Rates) Three Months Ended Dec. 31, 2021 Year Ended Dec. 31 2021 2020 2019 Borrowing limit $ 700 $ 700 $ 700 $ 700 Amount outstanding at period end 147 147 136 — Average amount outstanding 6 26 30 154 Maximum amount outstanding 150 322 230 432 Weighted average interest rate, computed on a daily basis 0.21 % 0.19 % 1.59 % 2.67 % Weighted average interest rate at end of period 0.22 0.22 0.20 N/A
Schedule Of Debt To Total Capitalization Ratio [Table Text Block]	Debt-to-Total Capitalization Ratio (a) Amount Facility May Be Increased (millions of dollars) Additional Periods for Which a One-Year Extension May Be Requested (b) 2021 2020 44 % 44 % $ 100 2 (a) The credit facility has a financial covenant requiring that the debt-to-total capitalization ratio be less than or equal to 65%.
Schedule of Line of Credit Facilities [Table Text Block]	(in millions of dollars): Credit Facility (a) Drawn (b) Available $ 700 $ 155 $ 545 (a) This credit facility matures in June 2024. (b) Includes letters of credit and outstanding commercial paper.	[1],[2]
Schedule of Capitalization [Table Text Block]	Long-term debt obligations for PSCo as of Dec. 31 (in millions of dollars): Financing Instrument Interest Rate Maturity Date 2021 2020 First mortgage bonds 2.25 % Sept. 15, 2022 $ 300 $ 300 First mortgage bonds 2.50 March 15, 2023 250 250 First mortgage bonds 2.90 May 15, 2025 250 250 First mortgage bonds 3.70 June 15, 2028 350 350 First mortgage bonds (b) 1.90 Jan. 15, 2031 375 375 First mortgage bonds (a) 1.875 June 15, 2031 750 — First mortgage bonds 6.25 Sept. 1, 2037 350 350 First mortgage bonds 6.50 Aug. 1, 2038 300 300 First mortgage bonds 4.75 Aug. 15, 2041 250 250 First mortgage bonds 3.60 Sept. 15, 2042 500 500 First mortgage bonds 3.95 March 15, 2043 250 250 First mortgage bonds 4.30 March 15, 2044 300 300 First mortgage bonds 3.55 June 15, 2046 250 250 First mortgage bonds 3.80 June 15, 2047 400 400 First mortgage bonds 4.10 June 15, 2048 350 350 First mortgage bonds 4.05 Sept. 15, 2049 400 400 First mortgage bonds 3.20 March 1, 2050 550 550 First mortgage bonds (b) 2.70 Jan. 15, 2051 375 375 Unamortized discount (33) (30) Unamortized debt issuance cost (50) (46) Current maturities (300) — Total long-term debt $ 6,167 $ 5,724 (a) 2021 financing. (b) 2020 financing.	[3],[4]
Schedule of Maturities of Long-term Debt [Table Text Block]	Maturities of long-term debt: (Millions of Dollars) 2022 $ 300 2023 250 2024 — 2025 250 2026 —
Preferred Stock	Capital Stock — PSCo has authorized the issuance of preferred stock. Preferred Stock Authorized (Shares) Par Value of Preferred Stock Preferred Stock Outstanding (Shares) 2021 and 2020 10,000,000 $ 0.01 —
[1]	Includes letters of credit and outstanding commercial paper.
[2]	This credit facility matures in June 2024.
[3]	2020 financing.
[4]	2021 financing

Revenues (Tables)

Revenues (Tables)	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	PSCo’s operating revenues consisted of the following: Year Ended Dec. 31, 2021 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 1,174 $ 816 $ 12 $ 2,002 C&I 1,660 308 30 1,998 Other 49 — — 49 Total retail 2,883 1,124 42 4,049 Wholesale 228 — — 228 Transmission 75 — — 75 Other 44 159 — 203 Total revenue from contracts with customers 3,230 1,283 42 4,555 Alternative revenue and other 183 72 5 260 Total revenues $ 3,413 $ 1,355 $ 47 $ 4,815 Year Ended Dec. 31, 2020 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 1,073 $ 650 $ 12 $ 1,735 C&I 1,512 225 27 1,764 Other 48 — — 48 Total retail 2,633 875 39 3,547 Wholesale 212 — — 212 Transmission 62 — — 62 Other 56 125 — 181 Total revenue from contracts with customers 2,963 1,000 39 4,002 Alternative revenue and other 153 24 4 181 Total revenues $ 3,116 $ 1,024 $ 43 $ 4,183 Year Ended Dec. 31, 2019 (Millions of Dollars) Electric Natural Gas All Other Total Major revenue types Revenue from contracts with customers: Residential $ 1,006 $ 750 $ 11 $ 1,767 C&I 1,579 281 28 1,888 Other 50 — — 50 Total retail 2,635 1,031 39 3,705 Wholesale 166 — — 166 Transmission 52 — — 52 Other 32 107 — 139 Total revenue from contracts with customers 2,885 1,138 39 4,062 Alternative revenue and other 148 23 4 175 Total revenues $ 3,033 $ 1,161 $ 43 $ 4,237

Preferred Stock (Tables)

Preferred Stock (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Preferred Stock	Capital Stock — PSCo has authorized the issuance of preferred stock. Preferred Stock Authorized (Shares) Par Value of Preferred Stock Preferred Stock Outstanding (Shares) 2021 and 2020 10,000,000 $ 0.01 —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Summary of Statute of Limitations Applicable to Open Tax Years	Tax Year(s) Expiration 2014 - 2016 December 2022 2018 September 2022
Reconciliation of Unrecognized Tax Benefits	Unrecognized tax benefits - permanent vs temporary: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 Unrecognized tax benefit — Permanent tax positions $ 9 $ 7 Unrecognized tax benefit — Temporary tax positions 2 2 Total unrecognized tax benefit $ 11 $ 9 Changes in unrecognized tax benefits: (Millions of Dollars) 2021 2020 2019 Balance at Jan. 1 $ 9 $ 12 $ 10 Additions based on tax positions related to the current year 2 2 1 Additions for tax positions of prior years — 6 1 Reductions for tax positions of prior years — (11) — Balance at Dec. 31 $ 11 $ 9 $ 12
Tax Benefits Associated with NOL and Tax Credit Carryforwards	Unrecognized tax benefits were reduced by tax benefits associated with NOL and tax credit carryforwards: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 NOL and tax credit carryforwards $ (11) $ (8)
Interest Payable related to Unrecognized Tax Benefits	Interest payable related to unrecognized tax benefits: (Millions of Dollars) 2021 2020 2019 Payable for interest related to unrecognized tax benefits at Jan. 1 $ — $ (1) $ (1) Interest income related to unrecognized tax benefits — 1 — Payable for interest related to unrecognized tax benefits at Dec. 31 $ — $ — $ (1)
NOL and Tax Credit Carryforwards	NOL amounts represent the tax loss that is carried forward and tax credits represent the deferred tax asset. NOL and tax credit carryforwards as of Dec. 31 were as follows: (Millions of Dollars) 2021 2020 Federal NOL carryforward $ 161 $ — Federal tax credit carryforwards 259 143 State NOL carryforwards 342 190 State tax credit carryforwards, net of federal detriment (a) 17 18 Valuation allowances for state credit carryforwards, net of federal benefit (b) (8) (8) (a) State tax credit carryforwards are net of federal detriment of $5 million as of Dec. 31, 2021 and 2020. (b) Valuation allowances for state tax credit carryforwards were net of federal benefit of $2 million as of Dec. 31, 2021 and 2020.
Schedule of Effective Income Tax Rate Reconciliation	Total income tax expense from operations differs from the amount computed by applying the statutory federal income tax rate to income before income tax expense. Effective income tax rate for years ended Dec. 31: 2021 2020 (a) 2019 (a) Federal statutory rate 21.0 % 21.0 % 21.0 % State income tax on pretax income, net of federal tax effect 3.6 3.6 3.6 Increases (decreases) in tax from: Wind PTCs (14.3) (10.3) (7.5) Plant regulatory differences (b) (4.6) (5.0) (3.3) Other tax credits, net NOL & tax credit allowances (1.0) (1.1) (1.3) Change in unrecognized tax benefits 0.3 (0.2) 0.3 Other, net (0.2) (0.9) (0.6) Effective income tax rate 4.8 % 7.1 % 12.2 % (a) Prior periods have been reclassified to conform to current year presentation. (b) Regulatory differences for income tax primarily relate to the credit of excess deferred taxes to customers through the average rate assumption method. Income tax benefits associated with the credit of excess deferred credits are offset by corresponding revenue reductions and additional prepaid pension asset amortization.
Schedule of Components of Income Tax Expense (Benefit)	Components of income tax expense for the years ended Dec. 31: (Millions of Dollars) 2021 2020 2019 Current federal tax expense (benefit) $ 16 $ 44 $ (9) Current state tax expense (benefit) — 4 (5) Current change in unrecognized tax benefit (1) (3) (1) Deferred federal tax (benefit) expense (13) (26) 61 Deferred state tax expense 31 26 33 Deferred change in unrecognized tax expense 3 2 3 Deferred ITCs (3) (2) (2) Total income tax expense $ 33 $ 45 $ 80 Components of deferred income tax expense as of Dec. 31: (Millions of Dollars) 2021 2020 2019 Deferred tax expense excluding items below $ 63 $ 46 $ 132 Amortization and adjustments to deferred income taxes on income tax regulatory assets and liabilities (42) (43) (35) Tax expense allocated to other comprehensive income, adoption of ASC Topic 326, and other — (1) — Deferred tax expense $ 21 $ 2 $ 97
Schedule of Deferred Tax Assets and Liabilities	Components of the net deferred tax liability as of Dec. 31: (Millions of Dollars) 2021 2020 (a) Deferred tax liabilities: Differences between book and tax bases of property $ 2,226 $ 2,132 Regulatory assets 258 257 Deferred fuel costs 126 (3) Operating lease assets 106 129 Pension expense and other employee benefits 23 19 Other 7 6 Total deferred tax liabilities $ 2,746 $ 2,540 Deferred tax assets: Regulatory liabilities $ 323 $ 319 Tax credit carryforward 276 161 Operating lease liabilities 106 129 Bad debts 10 8 NOL carryforward 46 7 Deferred ITCs 8 5 Tax credit valuation allowances (8) (8) Other 25 22 Total deferred tax assets $ 786 $ 643 Net deferred tax liability $ 1,960 $ 1,897 (a) Prior periods have been reclassified to conform to current year presentation.

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Gross Notional Amounts of Commodity Forwards and Options	Gross notional amounts of commodity forwards and options: (Amounts in Millions) (a)(b) Dec. 31, 2021 Dec. 31, 2020 MWh of electricity 15 17 MMBtu of natural gas 71 93 (a) Not reflective of net positions in the underlying commodities. (b) Notional amounts for options included on a gross basis, but are weighted for the probability of exercise.
Financial Impact of Qualifying Cash Flow Hedges on Accumulated Other Comprehensive Loss	(Millions of Dollars) 2021 2020 2019 Accumulated other comprehensive loss related to cash flow hedges at Jan. 1 $ (23) $ (24) $ (26) After-tax net realized losses on derivative transactions reclassified into earnings 2 1 2 Accumulated other comprehensive loss related to cash flow hedges at Dec. 31 $ (21) $ (23) $ (24)
Impact of Derivative Activity on Accumulated Other Comprehensive Loss, Regulatory Assets and Liabilities, and Income	Pre-Tax Fair Value Gains (Losses) Recognized During the Period in: (Millions of Dollars) Accumulated Other Regulatory (Assets) and Liabilities Year Ended Dec. 31, 2021 Other derivative instruments Natural gas commodity $ — $ (1) Total $ — $ (1) Year Ended Dec. 31, 2020 Other derivative instruments Natural gas commodity $ — $ (10) Total $ — $ (10) Year Ended Dec. 31, 2019 Other derivative instruments Natural gas commodity $ — $ (5) Total $ — $ (5) Pre-Tax (Gains) Losses (Millions of Dollars) Accumulated Loss Regulatory (Liabilities) Pre-Tax Gains (Losses) Recognized Year Ended Dec. 31, 2021 Derivatives designated as cash flow hedges Interest rate $ 2 (a) $ — $ — Total $ 2 $ — $ — Other derivative instruments Commodity trading $ — $ — $ 12 (b) Natural gas commodity — 4 (c) (15) (c) Total $ — $ 4 $ (3) Pre-Tax (Gains) Losses (Millions of Dollars) Accumulated Loss Regulatory (Liabilities) Pre-Tax Gains (Losses) Recognized Year Ended Dec. 31, 2020 Derivatives designated as cash flow hedges Interest rate $ 1 (a) $ — $ — Total $ 1 $ — $ — Other derivative instruments Commodity trading $ — $ — $ 3 (b) Natural gas commodity — 8 (c) (8) (c) Total $ — $ 8 $ (5) Pre-Tax (Gains) Losses (Millions of Dollars) Accumulated Loss Regulatory (Liabilities) Pre-Tax Gains (Losses) Recognized Year Ended Dec. 31, 2019 Derivatives designated as cash flow hedges Interest rate $ 2 (a) $ — $ — Total $ 2 $ — $ — Other derivative instruments Commodity trading $ — $ — $ 3 (b) Natural gas commodity — 1 (c) (4) (c) Total $ — $ 1 $ (1) (a) Recorded to interest charges. (b) Recorded to electric operating revenues. Portions of these gains and losses are subject to sharing with electric customers through margin-sharing mechanisms and deducted from gross revenue, as appropriate. (c)
Derivative Assets and Liabilities Measured at Fair Value on a Recurring Basis by Hierarchy Level	PSCo’s derivative assets and liabilities measured at fair value on a recurring basis were as follows: Dec. 31, 2021 Dec. 31, 2020 Fair Value Fair Value Total Netting (a) Total Fair Value Fair Value Total Netting (a) Total (Millions of Dollars) Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Current derivative assets Other derivative instruments: Commodity trading $ 12 $ 97 $ — $ 109 $ (81) $ 28 $ 1 $ 41 $ 1 $ 43 $ (28) $ 15 Natural gas commodity — 11 — 11 — 11 — 6 — 6 — 6 Total current derivative assets $ 12 $ 108 $ — $ 120 $ (81) $ 39 $ 1 $ 47 $ 1 $ 49 $ (28) $ 21 Noncurrent derivative assets Other derivative instruments: Commodity trading $ 10 $ 28 $ 54 $ 92 $ (65) $ 27 $ 1 $ 27 $ 8 $ 36 $ (20) $ 16 Total noncurrent derivative assets $ 10 $ 28 $ 54 $ 92 $ (65) 27 $ 1 $ 27 $ 8 $ 36 $ (20) $ 16 Current derivative liabilities Other derivative instruments: Commodity trading $ 6 $ 90 $ 16 $ 112 $ (85) $ 27 $ 1 $ 46 $ 7 $ 54 $ (33) $ 21 Natural gas commodity — 3 — 3 — 3 — 6 — 6 — 6 Total current derivative liabilities $ 6 $ 93 $ 16 $ 115 $ (85) $ 30 $ 1 $ 52 $ 7 $ 60 $ (33) $ 27 Noncurrent derivative liabilities Other derivative instruments: Commodity trading $ 3 $ — $ 101 $ 104 $ (75) $ 29 $ 1 $ 24 $ 46 $ 71 $ (20) $ 51 Total noncurrent derivative liabilities $ 3 $ — $ 101 $ 104 $ (75) $ 29 $ 1 $ 24 $ 46 $ 71 $ (20) $ 51 (a) PSCo nets derivative instruments and related collateral on its consolidated balance sheet when supported by a legally enforceable master netting agreement, and all derivative instruments and related collateral amounts were subject to master netting agreements at Dec. 31, 2021 and 2020. At Dec. 31, 2021 and 2020, derivative assets and liabilities include no obligations to return cash collateral, respectively. At Dec. 31, 2021 and 2020, derivative assets and liabilities include rights to reclaim cash collateral of $14 million and $5 million, respectively. The counterparty netting amounts presented exclude settlement receivables and payables and non-derivative amounts that may be subject to the same master netting agreements. Changes in Level 3 commodity derivatives for the years ended Dec. 31, 2021, 2020 and 2019: Year Ended Dec. 31 (Millions of Dollars) 2021 2020 2019 Balance at Jan. 1 $ (44) $ (13) $ — Settlements 4 — (2) Net transactions recorded during the period: Losses recognized in earnings (a) (23) (31) (11) Balance at Dec. 31 $ (63) $ (44) $ (13) (a) Level 3 losses recognized in earnings are subject to offsetting gains of derivative instruments categorized as levels 1 and 2 in the income statement. PSCo recognizes transfers between levels as of the beginning of each period. There were no transfers of amounts between levels for derivative instruments for the years ended Dec. 31, 2021, 2020 and 2019. Fair Value of Long-Term Debt As of Dec. 31, other financial instruments for which the carrying amount did not equal fair value: 2021 2020 (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt, including current portion $ 6,467 $ 7,291 $ 5,724 $ 7,040 Fair value of PSCo’s long-term debt is estimated based on recent trades and observable spreads from benchmark interest rates for similar securities. Fair value estimates are based on information available to management as of Dec. 31, 2021 and 2020, and given the observability of the inputs, fair values presented for long-term debt were assigned as Level 2.
Carrying Amount and Fair Value of Long-term Debt	2021 2020 (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt, including current portion $ 6,467 $ 7,291 $ 5,724 $ 7,040

Benefit Plans and Other Postr_2

Benefit Plans and Other Postretirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2021
Benefit Plans and Other Postretirement Benefits [Abstract]
Target Asset Allocations and Plan Assets Measured at Fair Value	, PSCo’s pension plan assets measured at fair value: Dec. 31, 2021 (a) Dec. 31, 2020 (a) (Millions of Dollars) Level 1 Level 2 Level 3 Measured at NAV Total Level 1 Level 2 Level 3 Measured at NAV Total Cash equivalents $ 49 $ — $ — $ — $ 49 $ 75 $ — $ — $ — $ 75 Commingled funds 492 — — 409 901 518 — — 388 906 Debt securities — 360 2 — 362 — 270 1 — 271 Equity securities 24 — — — 24 27 — — — 27 Other — 3 — 12 15 2 2 — — 4 Total $ 565 $ 363 $ 2 $ 421 $ 1,351 $ 622 $ 272 $ 1 $ 388 $ 1,283 (a) See Note 8 for further information on fair value measurement inputs and methods. Dec. 31, 2021 (a) Dec. 31, 2020 (a) (Millions of Dollars) Level 1 Level 2 Level 3 Measured at NAV Total Level 1 Level 2 Level 3 Measured at NAV Total Cash equivalents $ 25 $ — $ — $ — $ 25 $ 24 $ — $ — $ — $ 24 Insurance contracts — 46 — — 46 — 45 — — 45 Commingled funds 57 — — 68 125 64 — — 61 125 Debt securities — 194 1 — 195 — 207 — — 207 Other — 2 — — 2 — 3 — — 3 Total $ 82 $ 242 $ 1 $ 68 $ 393 $ 88 $ 255 $ — $ 61 $ 404 Pension Benefits Postretirement Benefits 2021 2020 2021 2020 Domestic and international equity securities 33 % 35 % 15 % 15 % Long-duration fixed income securities 37 35 — — Short-to-intermediate fixed income securities 11 13 71 72 Alternative investments 17 15 8 9 Cash 2 2 6 4 Total 100 % 100 % 100 % 100 %
Change in Projected Benefit Obligation	Pension Benefits Postretirement Benefits (Millions of Dollars) 2021 2020 2021 2020 Change in Benefit Obligation: Obligation at Jan. 1 $ 1,428 $ 1,330 $ 415 $ 380 Service cost 32 30 1 1 Interest cost 39 46 11 13 Plan amendments — — — — Actuarial (gain) loss (57) 102 (31) 52 Plan participants’ contributions — — 7 6 Medicare subsidy reimbursements — — 2 1 Benefit payments (79) (80) (36) (38) Obligation at Dec. 31 $ 1,363 $ 1,428 $ 369 $ 415 Change in Fair Value of Plan Assets: Fair value of plan assets at Jan. 1 $ 1,283 $ 1,124 $ 404 $ 401 Actual return on plan assets 102 189 15 32 Employer contributions 45 50 3 3 Plan participants’ contributions — — 7 6 Benefit payments (79) (80) (36) (38) Fair value of plan assets at Dec. 31 $ 1,351 $ 1,283 $ 393 $ 404 Funded status of plans at Dec. 31 $ (12) $ (145) $ 24 $ (11) Amounts recognized in the Consolidated Balance Sheet at Dec. 31: Noncurrent assets 6 — 24 — Noncurrent liabilities (18) (145) — (11) Net amounts recognized $ (12) $ (145) $ 24 $ (11)
Amounts Not Yet Recognized as Components of Net Periodic Benefit Costs Recorded on the Balance Sheet Based Upon Expected Recovery in Rates	Pension Benefits Postretirement Benefits (Millions of Dollars) 2021 2020 2021 2020 Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost: Net loss $ 313 $ 432 $ 48 $ 81 Prior service credit (1) (1) (2) (6) Total $ 312 $ 431 $ 46 $ 75 Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates: Current regulatory assets $ 24 $ 25 $ — $ — Noncurrent regulatory assets 288 404 46 75 Deferred income taxes — 1 — — Net-of-tax accumulated other comprehensive income — 1 — — Total $ 312 $ 431 $ 46 $ 75 Measurement date Dec. 31, 2021 Dec. 31, 2020 Dec. 31, 2021 Dec. 31, 2020
Components of Net Periodic Benefit Costs	Net Periodic Benefit Cost (Credit) — Net periodic benefit cost (credit), other than the service cost component, is included in other income (expense) in the statements of income. Components of net periodic benefit cost (credit) and amounts recognized in other comprehensive income and regulatory assets and liabilities: Pension Benefits Postretirement Benefits (Millions of Dollars) 2021 2020 2019 2021 2020 2019 Service cost $ 32 $ 30 $ 26 $ 1 $ — $ 1 Interest cost 39 46 52 11 13 15 Expected return on plan assets (73) (70) (69) (16) (17) (19) Amortization of prior service credit — (3) (3) (4) (4) (5) Amortization of net loss 32 30 25 3 1 3 Settlement charge (a) — — 3 — — — Net periodic pension cost (credit) 30 33 34 (5) (7) (5) Effects of regulation — 4 4 2 3 1 Net benefit cost (credit) recognized for financial reporting $ 30 $ 37 $ 38 $ (3) $ (4) $ (4) Significant Assumptions Used to Measure Costs: Discount rate 2.71 % 3.49 % 4.31 % 2.65 % 3.47 % 4.32 % Expected average long-term increase in compensation level 3.75 3.75 3.75 N/A N/A N/A Expected average long-term rate of return on assets 6.38 6.84 6.84 4.10 4.50 4.50 (a) A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. In 2019, as a result of lump-sum distributions during the plan year, PSCo recorded a total pension settlement ch arge of $3 million. A n immaterial amount was recorded in the income statement in 2019. There were no settlement charges recorded to the qualified pension plans in 2021 or 2020.
Projected Benefit Payments for the Pension and Postretirement Benefit Plans	PSCo’s projected benefit payments: (Millions of Dollars) Projected Gross Projected Expected Net Projected 2022 $ 83 $ 30 $ 2 $ 28 2023 82 29 2 27 2024 82 29 2 27 2025 82 28 2 26 2026 81 27 2 25 2027-2031 388 123 13 110

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Asset Retirement Obligations		PSCo’s AROs were as follows: 2021 (Millions Jan. 1, Accretion Cash Flow Revisions (a) Dec. 31, 2021 (b) Electric Steam, hydro and other production $ 137 $ 5 $ 10 $ 152 Wind 40 2 — 42 Distribution 15 1 — 16 Natural gas Transmission and distribution 203 9 (8) 204 Miscellaneous 3 — 5 8 Common Miscellaneous 1 (1) — — Total liability $ 399 $ 16 $ 7 $ 422 (a) In 2021, AROs were revised for changes in timing and estimates of cash flows. Revisions in steam, hydro, and other production AROs primarily related to changes in cost estimates for remediation of ash containment facilities. Changes in gas transmission and distribution AROs were primarily related to changes in labor rates coupled with increased gas line mileage and number of services. (b) There were no ARO amounts incurred or settled in 2021. 2020 (Millions Jan. 1, 2020 Amounts Incurred (a) Amounts Settled (b) Accretion Cash Flow Revisions (c) Dec. 31, 2020 Electric Steam, hydro and other production $ 100 $ — $ — $ 4 $ 33 $ 137 Wind 16 26 (3) 1 — 40 Distribution 14 — — 1 — 15 Natural gas Transmission and distribution 190 — — 8 5 203 Miscellaneous 3 — — — — 3 Common Miscellaneous 1 — — — — 1 Total liability $ 324 $ 26 $ (3) $ 14 $ 38 $ 399 (a) Amounts incurred related to the Cheyenne Ridge wind farm placed in service in 2020. (b) Amounts settled related to removal of wind facilities. (c) In 2020, AROs were revised for changes in timing and estimates of cash flows. Revisions in steam, hydro, and other production AROs primarily related to changes in cost estimates for remediation of ash containment facilities.
Assets and Liabilities, Lessee [Table Text Block]	Operating lease ROU assets: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 PPAs $ 600 $ 591 Other 77 68 Gross operating lease ROU assets 677 659 Accumulated amortization (268) (159) Net operating lease ROU assets $ 409 $ 500 Finance lease ROU assets: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 Gas storage facilities $ 201 $ 201 Gas pipeline 21 21 Gross finance lease ROU assets 222 222 Accumulated amortization (97) (90) Net finance lease ROU assets $ 125 $ 132
Lease, Cost [Table Text Block]	Components of lease expense: (Millions of Dollars) 2021 2020 2019 Operating leases PPA capacity payments $ 102 $ 100 $ 98 Other operating leases (a) 16 13 14 Total operating lease expense (b) $ 118 $ 113 $ 112 Finance leases Amortization of ROU assets $ 7 $ 7 $ 6 Interest expense on lease liability 17 18 19 Total finance lease expense $ 24 $ 25 $ 25 (a) Includes short-term lease expense of $1 million , $1 million and $2 million for 2021, 2020 and 2019, respectively.
Operating and Finance Lease Commitments, Maturity	Commitments under operating and finance leases as of Dec. 31, 2021: (Millions of Dollars) PPA (a) (b) Operating Leases Other Operating Leases Total Leases Finance Leases 2022 $ 84 $ 16 $ 100 $ 21 2023 70 11 81 20 2024 63 11 74 20 2025 63 5 68 19 2026 59 1 60 18 Thereafter 104 11 115 362 Total minimum obligation 443 55 498 460 Interest component of obligation (57) (6) (63) (335) Present value of minimum obligation $ 386 $ 49 435 125 Less current portion (84) (4) Noncurrent operating and finance lease liabilities $ 351 $ 121 Weighted-average remaining lease term in years 6.5 37.3 (a) Amounts do not include PPAs accounted for as executory contracts and/or contingent payments, such as energy payments on renewable PPAs. (b) PPA operating leases contractually expire at various dates through 2032.
Estimated Future Payments for Capacity and Energy Pursuant to Purchased Power Agreements	At Dec. 31, 2021, the estimated future payments for capacity that PSCo is obligated to purchase pursuant to these executory contracts, subject to availability, were as follows: (Millions of Dollars) Capacity 2022 $ 3 2023 3 2024 3 2025 3 2026 3 Thereafter 3 Total $ 18
Estimated Minimum Purchases Under Fuel Contracts	Estimated minimum purchases under these contracts as of Dec. 31, 2021: (Millions of Dollars) Coal Natural gas supply Natural gas storage and 2022 $ 186 $ 324 $ 116 2023 102 75 67 2024 67 3 37 2025 28 — 36 2026 29 — 35 Thereafter 30 — 440 Total $ 442 $ 402 $ 731

Other Comprehensive Income (Tab

Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
Changes in Accumulated Other Comprehensive Income (Loss), Net of Tax	Changes in accumulated other comprehensive loss, net of tax, for the years ended Dec. 31: 2021 (Millions of Dollars) Gains and Losses on Cash Flow Hedges Defined Benefit Pension and Postretirement Items Total Accumulated other comprehensive loss at Jan. 1 $ (23) $ (1) $ (24) Losses reclassified from net accumulated other comprehensive loss: Interest rate derivatives (net of taxes of $— and $—, respectively) 1 (a) — 1 Amortization of net actuarial loss (net of taxes of $— and $—, respectively) 1 — (b) 1 Net current period other comprehensive income (loss) 2 — 2 Accumulated other comprehensive loss at Dec. 31 $ (21) $ (1) $ (22) (a) Included in interest charges. (b) Included in the computation of net periodic pension and postretirement benefit costs. See Note 9 for further information. 2020 (Millions of Dollars) Gains and Losses on Cash Flow Hedges Defined Benefit Pension and Postretirement Items Total Accumulated other comprehensive loss at Jan. 1 $ (24) $ (3) $ (27) Losses (gains) reclassified from net accumulated other comprehensive loss: Interest rate derivatives (net of taxes of $— and $—, respectively) 1 (a) — 1 Amortization of net actuarial gains (net of taxes of $— and $1, respectively) — 2 (b) 2 Net current period other comprehensive income 1 2 3 Accumulated other comprehensive loss at Dec. 31 $ (23) $ (1) $ (24) (a) Included in interest charges. (b) Included in the computation of net periodic pension and postretirement benefit costs. See Note 9 for further information.

Segments and Related Informat_2

Segments and Related Information (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Results from Operations by Reportable Segment	PSCo’s segment information: (Millions of Dollars) 2021 2020 2019 Regulated Electric Operating revenues — external $ 3,413 $ 3,116 $ 3,033 Intersegment revenue 1 1 1 Total revenues $ 3,414 $ 3,117 $ 3,034 Depreciation and amortization 566 497 455 Interest charges and financing costs 179 173 173 Income tax (benefit) expense (16) 13 45 Net income 495 460 465 Regulated Natural Gas Total revenues $ 1,355 $ 1,024 $ 1,161 Depreciation and amortization 171 152 141 Interest charges and financing costs 53 50 50 Income tax expense 45 29 33 Net income 168 126 119 All Other Total revenues (a) $ 47 $ 43 $ 43 Depreciation and amortization 7 6 6 Interest charges and financing costs 2 1 1 Income tax expense 4 3 2 Net (loss) income (3) 2 (6) Consolidated Total Total revenues (a) $ 4,816 $ 4,184 $ 4,238 Reconciling eliminations (1) (1) (1) Total operating revenues $ 4,815 $ 4,183 $ 4,237 Depreciation and amortization 744 655 602 Interest charges and financing costs 234 224 224 Income tax expense 33 45 80 Net income 660 588 578 (a) Operating revenues include $5 million of other affiliate revenue for the years ended Dec. 31, 2021, 2020 and 2019, respectively. See Note 13 for further information.

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Related Party Transactions	Significant affiliate transactions among the companies and related parties for the years ended Dec. 31: (Millions of Dollars) 2021 2020 2019 Operating revenues: Other $ 5 $ 5 $ 5 Operating expenses: Other operating expenses — paid to Xcel Energy Services Inc. 617 571 532 Accounts receivable and payable with affiliates at Dec. 31: 2021 2020 (Millions of Dollars) Accounts Receivable Accounts Payable Accounts Receivable Accounts Payable NSP-Minnesota $ — $ 16 $ — $ 1 NSP-Wisconsin — 2 — 1 SPS — 7 — 6 Other subsidiaries of Xcel Energy Inc. 13 44 8 50 $ 13 $ 69 $ 8 $ 58

Summarized Quarterly Financia_2

Summarized Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Summarized Quarterly Financial Data (Unaudited)	Quarter Ended (Millions of Dollars) March 31, 2021 June 30, 2021 Sept. 30, 2021 Dec. 31, 2021 Operating revenues $ 1,057 $ 911 $ 1,081 $ 1,134 Operating income 196 161 290 176 Net income 129 108 218 133 Quarter Ended (Millions of Dollars) March 31, 2020 June 30, 2020 Sept. 30, 2020 Dec. 31, 2020 Operating revenues $ 1,057 $ 911 $ 1,081 $ 1,134 Operating income 196 161 290 176 Net income 129 108 218 133

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Depreciation expense expressed as a percentage of average depreciable property	3.20%	3.10%	2.90%
Cash and Cash Equivalents [Abstract]
Maximum number of months remaing	$ 3
Accounts and Financing Receivable, after Allowance for Credit Loss, Current and Noncurrent [Abstract]
Accounts Receivable, Allowance for Credit Loss, Current	$ 40,000,000	$ 29,000,000
Alternative Revenue Programs [Abstract]
Number of DSM Products, Commercial and Industrial Customers	20
Number of DSM Products, Residential and Low-income Customers	23
maximum number of months following end of annual period in which revenues are to be included	$ 24
DSM Measurements	1,000
Public Utilities, Inventory [Line Items]
Inventories	$ 245,000,000	189,000,000
Materials and supplies
Public Utilities, Inventory [Line Items]
Inventories	70,000,000	63,000,000
Public Utilities, Inventory, Fuel [Member]
Public Utilities, Inventory [Line Items]
Inventories	71,000,000	73,000,000
Public Utilities, Inventory, Natural Gas [Member]
Public Utilities, Inventory [Line Items]
Inventories	$ 104,000,000	$ 53,000,000

Accounting Pronouncements - Rec

Accounting Pronouncements - Recently Adopted (Details) $ in Millions	Jan. 01, 2020USD ($)
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Credit Losses, Topic 326 (ASC Topic 326)	$ 1

Property Plant and Equipment _3

Property Plant and Equipment Property Plant and Equipment (Details) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment		$ 24,101	$ 22,699
Accumulated depreciation		5,657	5,229
Property, plant and equipment, net		18,444	17,470
Electric plant
Property, Plant and Equipment [Line Items]
Property, plant and equipment		16,543	15,736
Natural gas plant
Property, Plant and Equipment [Line Items]
Property, plant and equipment		5,471	5,037
Common and other property
Property, Plant and Equipment [Line Items]
Property, plant and equipment		1,224	1,191
Plant to be retired
Property, Plant and Equipment [Line Items]
Property, plant and equipment	[1]	182	225
CWIP
Property, Plant and Equipment [Line Items]
Property, plant and equipment		$ 681	$ 510
[1]	Includes regulator-approved retirements of Comanche Units 1 and 2 and jointly owned Craig Unit 1. Also includes PSCo’s planned retirement of jointly owned Craig Unit 2.

Property Plant and Equipment Jo

Property Plant and Equipment Joint Ownership (Details) $ in Millions	Dec. 31, 2021USD ($)
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 1,626	[1]
Accumulated Depreciation	506	[1]
Electric Generation | Hayden Unit 1
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	156
Accumulated Depreciation	$ 99
Percent Owned	76.00%
Electric Generation | Hayden Unit 2
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 151
Accumulated Depreciation	$ 78
Percent Owned	37.00%
Electric Generation | Hayden Common Facilities
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 42
Accumulated Depreciation	$ 27
Percent Owned	53.00%
Electric Generation | Craig Units 1 and 2
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 81
Accumulated Depreciation	$ 48
Percent Owned	10.00%
Electric Generation | Craig Common Facilities 1, 2 and 3
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 39
Accumulated Depreciation	$ 25
Percent Owned	7.00%
Electric Generation | Comanche Unit 3
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 917
Accumulated Depreciation	$ 154
Percent Owned	67.00%
Electric Generation | Comanche Common Facilities
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 28
Accumulated Depreciation	$ 2
Percent Owned	82.00%
Electric Transmission | Transmission and Other Facilities
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 182
Accumulated Depreciation	63
Gas Transportation | Rifle to Avon
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	22
Accumulated Depreciation	$ 8
Percent Owned	60.00%
Gas Transportation | Gas Transportation Compressor
Jointly Owned Utility Plant Interests [Line Items]
Plant in Service	$ 8
Accumulated Depreciation	$ 2
Percent Owned	50.00%
[1]	Projects additionally include $3 million in CWIP.

Regulatory Assets and Liabili_3

Regulatory Assets and Liabilities, Regulatory Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 353	$ 121
Regulatory Asset, Noncurrent		1,293	1,059
Regulatory assets not currently earning a return		639	195
Pension and Retiree Medical Obligations
Regulatory Assets [Line Items]
Regulatory Asset, Current		26	28
Regulatory Asset, Noncurrent		331	478
Recoverable Purchased Natural Gas and Electric Energy Costs
Regulatory Assets [Line Items]
Regulatory Asset, Current		218	6
Regulatory Asset, Noncurrent		$ 320	0
Recoverable Purchased Natural Gas and Electric Energy Costs | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		3 years
Recoverable Purchased Natural Gas and Electric Energy Costs | Maximum
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		1 year
Depreciation differences
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 16	16
Regulatory Asset, Noncurrent		$ 173	154
Depreciation differences | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		1 year
Depreciation differences | Maximum
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		10 years
Net AROs
Regulatory Assets [Line Items]
Regulatory Asset, Current	[1]	$ 0	0
Regulatory Asset, Noncurrent	[1]	154	132
Recoverable Deferred Taxes on AFUDC Recorded in Plant
Regulatory Assets [Line Items]
Regulatory Asset, Current		0	0
Regulatory Asset, Noncurrent		116	110
Excess deferred taxes - TCJA
Regulatory Assets [Line Items]
Regulatory Asset, Current		2	3
Regulatory Asset, Noncurrent		56	56
Purchased Power Agreements
Regulatory Assets [Line Items]
Regulatory Asset, Current		3	3
Regulatory Asset, Noncurrent		19	22
Property Tax
Regulatory Assets [Line Items]
Regulatory Asset, Current		16	16
Regulatory Asset, Noncurrent		16	21
Gas pipeline inspection costs
Regulatory Assets [Line Items]
Regulatory Asset, Current		0	0
Regulatory Asset, Noncurrent		$ 12	9
Gas pipeline inspection costs | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		1 year
Gas pipeline inspection costs | Maximum
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		2 years
Conservation programs
Regulatory Assets [Line Items]
Regulatory Asset, Current	[2]	$ 11	11
Regulatory Asset, Noncurrent	[2]	$ 11	11
Conservation programs | Minimum
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		1 year
Conservation programs | Maximum
Regulatory Assets [Line Items]
Regulatory Asset, Amortization Period		2 years
Losses on Reacquired Debt
Regulatory Assets [Line Items]
Regulatory Asset, Current		$ 1	1
Regulatory Asset, Noncurrent		2	3
Contract Valuation Adjustments
Regulatory Assets [Line Items]
Regulatory Asset, Current	[3]	3	6
Regulatory Asset, Noncurrent	[3]	0	0
Other
Regulatory Assets [Line Items]
Regulatory Asset, Current		57	31
Regulatory Asset, Noncurrent		$ 83	$ 63
[1]	Includes amounts recorded for future recovery of AROs.
[2]	Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions.
[3]	Includes the fair value of certain long-term PPAs used to meet energy capacity requirements and valuation adjustments on natural gas commodity purchases.

Regulatory Assets and Liabili_4

Regulatory Assets and Liabilities, Regulatory Liabilities (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	[1]	$ 95	$ 100
Regulatory Liability, Noncurrent	[1]	2,397	2,337
Other Current Liabilities
Regulatory Liabilities [Line Items]
Entity's Recorded Provision for Revenue Subject To Refund		2	0
Deferred Income Tax Adjustments and TCJA Refunds
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	[2]	2	5
Regulatory Liability, Noncurrent	[2]	1,328	1,368
Plant Removal Costs
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		0	0
Regulatory Liability, Noncurrent		651	615
Effects of regulation on employee benefit costs
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	[3]	0	0
Regulatory Liability, Noncurrent	[3]	216	203
Renewable Resources and Environmental Initiatives
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		0	0
Regulatory Liability, Noncurrent		91	59
ITC Deferrals
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		0	0
Regulatory Liability, Noncurrent		42	40
Sales True Up and Revenue Decoupling [Member]
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		9	10
Regulatory Liability, Noncurrent		$ 41	41
Sales True Up and Revenue Decoupling [Member] | Minimum
Regulatory Liabilities [Line Items]
Regulatory Liability, Amortization Period		1 year
Sales True Up and Revenue Decoupling [Member] | Maximum
Regulatory Liabilities [Line Items]
Regulatory Liability, Amortization Period		2 years
Conservation programs
Regulatory Liabilities [Line Items]
Regulatory Liability, Current	[4]	$ 34	39
Regulatory Liability, Noncurrent	[4]	0	0
Deferred Electric, Gas, and Steam Production Costs
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		29	17
Regulatory Liability, Noncurrent		0	0
Other
Regulatory Liabilities [Line Items]
Regulatory Liability, Current		21	29
Regulatory Liability, Noncurrent		$ 28	$ 11
[1]	Revenue subject to refund of $2 million for 2021 is included in other current liabilities and none for 2020
[2]	Includes the revaluation of recoverable/regulated plant accumulated deferred income taxes and revaluation impact of non-plant accumulated deferred income taxes due to the TCJA.
[3]	Includes regulatory amortization and certain 2018 TCJA benefits approved by the CPUC to offset the prepaid pension asset.
[4]	Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions.

Borrowings and Other Financin_3

Borrowings and Other Financing Instruments, Short-Term Borrowings (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Short-term Debt [Line Items]
Short-term debt	$ 147	$ 147	$ 136
Letter of Credit
Short-term Debt [Line Items]
Line of Credit Facility, Expiration Period		1 year
Commercial Paper [Member]
Short-term Debt [Line Items]
Borrowing limit	700	$ 700	700	$ 700
Short-term debt	147	147	136	0
Average amount outstanding	$ 6	$ 26	$ 30	$ 154
Weighted average interest rate at period end (percentage)	0.22%	0.22%		0.20%
Line of Credit Facility, Interest Rate During Period	0.21%	0.19%	1.59%	2.67%
Maximum amount outstanding	$ 150	$ 322	$ 230	$ 432
Money Pool
Short-term Debt [Line Items]
Borrowing limit	250	250	250	250
Short-term debt	0	0	57	39
Average amount outstanding	$ 14	$ 12	$ 59	$ 7
Weighted average interest rate at period end (percentage)			0.70%	1.63%
Line of Credit Facility, Interest Rate During Period	0.05%	0.07%	0.60%	2.29%
Maximum amount outstanding	$ 74	$ 243	$ 250	$ 50

Borrowings and Other Financin_4

Borrowings and Other Financing Instruments, Letters of Credit (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Line of Credit Facility [Line Items]
Amount outstanding at period end	$ 147	$ 136
Letter of Credit
Line of Credit Facility [Line Items]
Amount outstanding at period end	$ 8	$ 8
Letter of Credit
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Period	1 year

Borrowings and Other Financin_5

Borrowings and Other Financing Instruments, Credit Facility (Details) - Credit Facility $ in Millions		12 Months Ended
		Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Line of Credit Facility [Line Items]
Line Of Credit Facility Debt To Total Capitalization Ratio (as a percent)	[1]	44.00%	44.00%
Number Of Additional Periods Revolving Termination Date Can Be Extended Subject To Majority Bank Group Approval	[2]	2
Line Of Credit Facility Maximum Amount Credit Facility May Be Increased		$ 100
Line Of Credit Facility Maximum Debt To Total Capitalization Ratio Allowed		65.00%
Direct advances on the credit facility outstanding		$ 0	$ 0
PSCo [Member]
Line of Credit Facility [Line Items]
Credit facility	[3]	700
Drawn	[4]	155
Available		$ 545
PSCo [Member]
Line of Credit Facility [Line Items]
Line Of Credit Facility Minimum Threshhold Percentage Of Subsidiary Assets To Consolidated Assets Required To Initiate Cross Default Provisions		15.00%
Line of Credit Facility, Minimum Amount of Indebtedness in Default to Initiate Cross Default Provisions		$ 75
[1]	The credit facility has a financial covenant requiring that the debt-to-total capitalization ratio be less than or equal to 65%.
[2]	All extension requests are subject to majority bank group approval.
[3]	This credit facility matures in June 2024.
[4]	Includes letters of credit and outstanding commercial paper.

Borrowings and Other Financin_6

Borrowings and Other Financing Instruments, Long-Term Borrowings (Details) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount (Premium), Net		$ (33)	$ (30)
Unamortized Debt Issuance Expense		(50)	(46)
Long-term Debt, Current Maturities		(300)	0
Long-term Debt		6,167	5,724
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months		300
Long-term Debt, Maturities, Repayments of Principal in Year Two		250
Long-term Debt, Maturities, Repayments of Principal in Year Three		0
Long-term Debt, Maturities, Repayments of Principal in Year Four		250
Long-term Debt, Maturities, Repayments of Principal in Year Five		0
Deferred Finance Costs, Noncurrent, Net		50	46
First Mortgage Bonds | Series Due Sept. 15, 2022 [Member]
Debt Instrument [Line Items]
Face amount		$ 300	300
Interest rate, stated percentage (in hundredths)		2.25%
First Mortgage Bonds | Series Due March 15, 2023 [Member]
Debt Instrument [Line Items]
Face amount		$ 250	250
Interest rate, stated percentage (in hundredths)		2.50%
First Mortgage Bonds | Series Due May 15, 2025 [Member]
Debt Instrument [Line Items]
Face amount		$ 250	250
Interest rate, stated percentage (in hundredths)		2.90%
First Mortgage Bonds | Series Due June 15, 2028 [Member]
Debt Instrument [Line Items]
Face amount		$ 350	350
Interest rate, stated percentage (in hundredths)		3.70%
First Mortgage Bonds | Series Due Jan. 15, 2031 [Member]
Debt Instrument [Line Items]
Face amount	[1]	$ 375	375
Interest rate, stated percentage (in hundredths)	[1]	1.90%
First Mortgage Bonds | Series Due Sept. 1, 2037 [Member]
Debt Instrument [Line Items]
Face amount		$ 350	350
Interest rate, stated percentage (in hundredths)		6.25%
First Mortgage Bonds | Series Due Aug. 1, 2038 [Member]
Debt Instrument [Line Items]
Face amount		$ 300	300
Interest rate, stated percentage (in hundredths)		6.50%
First Mortgage Bonds | Series Due Aug. 15, 2041 [Member]
Debt Instrument [Line Items]
Face amount		$ 250	250
Interest rate, stated percentage (in hundredths)		4.75%
First Mortgage Bonds | Series Due Sept. 15, 2042 [Member]
Debt Instrument [Line Items]
Face amount		$ 500	500
Interest rate, stated percentage (in hundredths)		3.60%
First Mortgage Bonds | Series Due March 15, 2043 [Member]
Debt Instrument [Line Items]
Face amount		$ 250	250
Interest rate, stated percentage (in hundredths)		3.95%
First Mortgage Bonds | Series Due March 15, 2044 [Member]
Debt Instrument [Line Items]
Face amount		$ 300	300
Interest rate, stated percentage (in hundredths)		4.30%
First Mortgage Bonds | Series Due June 15, 2046 [Member]
Debt Instrument [Line Items]
Face amount		$ 250	250
Interest rate, stated percentage (in hundredths)		3.55%
First Mortgage Bonds | Series Due June 15, 2047 [Member]
Debt Instrument [Line Items]
Face amount		$ 400	400
Interest rate, stated percentage (in hundredths)		3.80%
First Mortgage Bonds | Series Due June 15, 2048 [Member]
Debt Instrument [Line Items]
Face amount		$ 350	350
Interest rate, stated percentage (in hundredths)		4.10%
First Mortgage Bonds | Series Due September 15, 2049 [Domain]
Debt Instrument [Line Items]
Face amount		$ 400	400
Interest rate, stated percentage (in hundredths)		4.05%
First Mortgage Bonds | Series Due March 1, 2050 [Domain]
Debt Instrument [Line Items]
Face amount		$ 550	550
Interest rate, stated percentage (in hundredths)		3.20%
First Mortgage Bonds | Series Due Jan. 15, 2051 [Member]
Debt Instrument [Line Items]
Face amount	[1]	$ 375	375
Interest rate, stated percentage (in hundredths)	[1]	2.70%
First Mortgage Bonds | Series Due June 15, 2031
Debt Instrument [Line Items]
Face amount	[2]	$ 750	0
Interest rate, stated percentage (in hundredths)	[2]	1.875%
Long-term Debt
Debt Instrument [Line Items]
Long-term Debt		$ 6,167	$ 5,724
[1]	2020 financing.
[2]	2021 financing

Borrowings and Other Financin_7

Borrowings and Other Financing Instruments Preferred Stock (Details) - PSCo [Member] - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Preferred Stock [Abstract]
Preferred Stock, Shares Authorized	10,000,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01
Preferred stock, shares outstanding (in shares)	0	0
Debt Instrument [Line Items]
Preferred Stock, Shares Authorized	10,000,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01
Preferred stock, shares outstanding (in shares)	0	0

Revenues (Details)

Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Retail
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	$ 4,049	$ 3,547	$ 3,705
Retail | Residential
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	2,002	1,735	1,767
Retail | C&I
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	1,998	1,764	1,888
Retail | Other
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	49	48	50
Wholesale
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	228	212	166
Transmission
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	75	62	52
Other
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	203	181	139
Total revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	4,555	4,002	4,062
Alternative revenue and other
Disaggregation of Revenue [Line Items]
Alternative revenue and other	260	181	175
Regulated Electric | Retail
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	2,883	2,633	2,635
Regulated Electric | Retail | Residential
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	1,174	1,073	1,006
Regulated Electric | Retail | C&I
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	1,660	1,512	1,579
Regulated Electric | Retail | Other
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	49	48	50
Regulated Electric | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	228	212	166
Regulated Electric | Transmission
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	75	62	52
Regulated Electric | Other
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	44	56	32
Regulated Electric | Total revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	3,230	2,963	2,885
Regulated Electric | Alternative revenue and other
Disaggregation of Revenue [Line Items]
Alternative revenue and other	183	153	148
Regulated Natural Gas | Retail
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	1,124	875	1,031
Regulated Natural Gas | Retail | Residential
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	816	650	750
Regulated Natural Gas | Retail | C&I
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	308	225	281
Regulated Natural Gas | Retail | Other
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	0	0	0
Regulated Natural Gas | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	0	0	0
Regulated Natural Gas | Transmission
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	0	0	0
Regulated Natural Gas | Other
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	159	125	107
Regulated Natural Gas | Total revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	1,283	1,000	1,138
Regulated Natural Gas | Alternative revenue and other
Disaggregation of Revenue [Line Items]
Alternative revenue and other	72	24	23
All Other | Retail
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	42	39	39
All Other | Retail | Residential
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	12	12	11
All Other | Retail | C&I
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	30	27	28
All Other | Retail | Other
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	0	0	0
All Other | Wholesale
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	0	0	0
All Other | Transmission
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	0	0	0
All Other | Other
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	0	0	0
All Other | Total revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	42	39	39
All Other | Alternative revenue and other
Disaggregation of Revenue [Line Items]
Alternative revenue and other	5	4	4
Total revenues
Disaggregation of Revenue [Line Items]
Total revenues	4,815	4,183	4,237
Total revenues | Regulated Electric
Disaggregation of Revenue [Line Items]
Total revenues	3,413	3,116	3,033
Total revenues | Regulated Natural Gas
Disaggregation of Revenue [Line Items]
Total revenues	1,355	1,024	1,161
Total revenues | All Other
Disaggregation of Revenue [Line Items]
Total revenues	$ 47	$ 43	$ 43

State Audits

State Audits	12 Months Ended
	Dec. 31, 2021USD ($)
Income Tax Disclosure [Abstract]
Potential Tax Adjustments	$ 0

Unrealized Tax Benefits

Unrealized Tax Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2021	Jan. 01, 2020	Jan. 01, 2019
Income Tax Disclosure [Abstract]
Upper bound of decrease in unrecognized tax benefit that is reasonably possible	$ 2
Unrecognized Tax Benefits, Income Tax Penalties Expense	0	$ 0	$ 0
Unrecognized tax benefit — Permanent tax positions	9	7
Unrecognized tax benefit — Temporary tax positions	2	2
Total unrecognized tax benefit	11	9	12	$ 9	$ 12	$ 10
Additions based on tax positions related to the current year	2	2	1
Additions for tax positions of prior years	0	6	1
Reductions for tax positions of prior years	0	(11)	0
NOL and tax credit carryforwards	(11)	(8)
Payable for interest related to unrecognized tax benefits	0	0	(1)	$ 0	$ (1)	$ (1)
Unrecognized Tax Benefits, Interest on Income Taxes Expense	$ 0	$ 1	$ 0

Other Income Tax Matters

Other Income Tax Matters - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Income Tax Examination [Line Items]
Federal detriment		$ 5	$ 5
Federal Benefit		2	2
Federal NOL carryforward		161	0
Federal tax credit carryforwards		259	143
State NOL carryforwards		342	190
state tax credit carryforward, net of federal detirment	[1]	17	18
valuation allowances for state credit carryforwards, net of federal benefit	[2]	$ (8)	$ (8)
Federal statutory rate		21.00%	21.00%	[3]	21.00%	[3]
State income tax on pretax income, net of federal tax effect		3.60%	3.60%	[3]	3.60%	[3]
Wind PTCs		(14.30%)	(10.30%)	[3]	(7.50%)	[3]
Plant regulatory differences (b)	[4]	(4.60%)	(5.00%)	[3]	(3.30%)	[3]
Other tax credits, net NOL & tax credit allowances		(1.00%)	(1.10%)	[3]	(1.30%)	[3]
Change in unrecognized tax benefits		0.30%	(0.20%)	[3]	0.30%	[3]
Other, net		(0.20%)	(0.90%)	[3]	(0.60%)	[3]
Effective income tax rate		4.80%	7.10%	[3]	12.20%	[3]
Total income tax expense		$ 33	$ 45		$ 80
Deferred tax expense excluding items below		63	46		132
Amortization and adjustments to deferred income taxes on income tax regulatory assets and liabilities		(42)	(43)		(35)
Tax expense allocated to other comprehensive income, adoption of ASC Topic 326, and other		0	(1)		0
Total deferred tax assets		21	2		97
Deferred fuel costs		126	(3)	[3]
Operating lease liabilities		435
Bad debts		10	8	[5]
Tax credit valuation allowances		(8)	(8)	[5]
income tax expense [Member]
Income Tax Examination [Line Items]
Current federal tax expense (benefit)		16	44		(9)
Current state tax expense (benefit)		0	4		(5)
Current change in unrecognized tax benefit		(1)	(3)		(1)
Deferred federal tax (benefit) expense		(13)	(26)		61
Deferred state tax expense		31	26		33
Deferred change in unrecognized tax expense		3	2		3
Deferred ITCs		3	2		(2)
Total income tax expense		33	45		$ 80
Net Deferred Tax Liablility [Member]
Income Tax Examination [Line Items]
Deferred ITCs		(8)	(5)	[5]
Total deferred tax assets		786	643	[5]
Differences between book and tax bases of property		2,226	2,132	[5]
Regulatory assets		258	257	[5]
Operating lease assets		106	129	[5]
Pension expense and other employee benefits		23	19	[5]
Other		7	6	[5]
Total deferred tax liabilities		2,746	2,540	[5]
Regulatory liabilities		323	319	[5]
Tax credit carryforward		276	161	[5]
Operating lease liabilities		106	129	[5]
NOL carryforward		46	7	[5]
Other		25	22	[5]
Net deferred tax liability		$ 1,960	$ 1,897	[5]
[1]	State tax credit carryforwards are net of federal detriment of $5 million as of Dec. 31, 2021 and 2020.
[2]	Valuation allowances for state tax credit carryforwards were net of federal benefit of $2 million as of Dec. 31, 2021 and 2020.
[3]	(a) Prior periods have been reclassified to conform to current year presentation.
[4]	Regulatory differences for income tax primarily relate to the credit of excess deferred taxes to customers through the average rate assumption method. Income tax benefits associated with the credit of excess deferred credits are offset by corresponding revenue reductions and additional prepaid pension asset amortization.
[5]	Prior periods have been reclassified to conform to current year presentation.

Interest Rate Derivatives (Deta

Interest Rate Derivatives (Details) $ in Millions	Dec. 31, 2021USD ($)
Interest Rate Swap
Derivative [Line Items]
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	$ 1

Commodity Derivatives (Details)

Commodity Derivatives (Details) MWh in Millions, MMBTU in Millions, $ in Millions		Dec. 31, 2021USD ($)MWhMMBTU	Dec. 31, 2020MWhMMBTU
Derivative [Line Items]
Cash Flow Hedges Derivative Instruments at Fair Value, Net | $		$ 0
Electric Commodity
Derivative [Line Items]
Notional Amount | MWh	[1],[2]	15	17
Natural Gas Commodity
Derivative [Line Items]
Notional Amount | MMBTU	[1],[2]	71	93
[1]	Not reflective of net positions in the underlying commodities.
[2]	Notional amounts for options included on a gross basis, but are weighted for the probability of exercise.

Consideration of Credit Risk an

Consideration of Credit Risk and Concentrations (Details) - Credit Concentration Risk $ in Millions	Dec. 31, 2021USD ($)Counterparty
Derivative [Line Items]
Number of most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure	10
Municipal or Cooperative Entities or Other Utilities
Derivative [Line Items]
Number of most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure	7
External Credit Rating, Investment Grade
Derivative [Line Items]
Number of most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure	4
Wholesale, trading and non trading commodity credit exposure for the most significant counterparties | $	$ 53
Percentage of wholesale, trading and non trading commodity credit exposure for the most significant counterparties	40.00%
No Investment Grade Ratings from External Credit Rating Agencies
Derivative [Line Items]
Number of most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure	5
Wholesale, trading and non trading commodity credit exposure for the most significant counterparties | $	$ 20
Percentage of wholesale, trading and non trading commodity credit exposure for the most significant counterparties	15.00%
External Credit Rating, Non Investment Grade [Member]
Derivative [Line Items]
Number of most significant counterparties for wholesale, trading and non-trading commodity activities with credit exposure	1
Wholesale, trading and non trading commodity credit exposure for the most significant counterparties | $	$ 38
Percentage of wholesale, trading and non trading commodity credit exposure for the most significant counterparties	29.00%

Qualifying Cash Flow Hedges (De

Qualifying Cash Flow Hedges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financial Impact of Qualifying Cash Flow Hedges on Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Beginning Balance	$ (23)	$ (24)	$ (26)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	2	1	2
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Ending Balance	(21)	(23)	(24)
Impact of Derivative Activity [Abstract]
Fair Value Hedges, Net	0	0	0
Not Designated as Hedging Instrument
Impact of Derivative Activity [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	0	0	0
Derivative Instruments Gain (Loss) Reclassified To Regulatory Assets And Liabilities Net	(1)	(10)	(5)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	0	0
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)	(4)	(8)	1
Derivative, Gain (Loss) on Derivative, Net	(3)	(5)	(1)
Not Designated as Hedging Instrument | Commodity Trading Contract
Impact of Derivative Activity [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	0	0
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)	0	0	0
Derivative, Gain (Loss) on Derivative, Net	12	3	3	[1]
Not Designated as Hedging Instrument | Natural Gas Commodity Contract
Impact of Derivative Activity [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	0	0	0
Derivative Instruments Gain (Loss) Reclassified To Regulatory Assets And Liabilities Net	(1)	(10)	(5)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	0	0
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)	(4)	(8)	(1)
Derivative, Gain (Loss) on Derivative, Net	(15)	(8)	(4)
Designated as Hedging Instrument | Cash Flow Hedges
Impact of Derivative Activity [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(2)	(1)	(2)
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)	0	0	0
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Designated as Hedging Instrument | Cash Flow Hedges | Interest Rate Contract
Impact of Derivative Activity [Abstract]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(2)	(1)	(2)	[2]
Pre-tax gains (losses) reclassified into income during the period from regulatory assets and (liabilities)	0	0	0
Derivative, Gain (Loss) on Derivative, Net	$ 0	$ 0	$ 0
[1]	Recorded to electric operating revenues. Portions of these gains and losses are subject to sharing with electric customers through margin-sharing mechanisms and deducted from gross revenue, as appropriate.
[2]	Recorded to interest charges.

Credit Related Contingent Featu

Credit Related Contingent Features (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Derivative, Gross Liability Position, Aggregate Fair Value	$ 0	$ 0
Derivative, Gross Liability with Cross Default Position, Aggregate Fair Value	16	46
Collateral Already Posted Adequate Assurance Clauses Aggregate Fair Value	$ 0	$ 0

Recurring Fair Value Measuremen

Recurring Fair Value Measurements (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Return Cash Collateral		$ 0	$ 0
Reclaim Cash Collateral		14	5
Commodity Contract
Derivatives, Fair Value [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs, Beginning Balance		(44)	(13)	$ 0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements		4	0	(2)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	[1]	(23)	(31)	(11)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs, Ending Balance		(63)	(44)	(13)
Transfers Between Levels, Net		0	0	$ 0
Fair Value Measured on a Recurring Basis | Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		120	49
Netting	[2]	(81)	(28)
Derivative Asset, Net		39	21
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 1
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		12	1
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		108	47
Fair Value Measured on a Recurring Basis | Other Current Assets | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0	1
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Commodity Contract
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		109	43
Netting	[2]	(81)	(28)
Derivative Asset, Net		28	15
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Commodity Contract | Level 1
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		12	1
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Commodity Contract | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		97	41
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Commodity Contract | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0	1
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Natural Gas Commodity Contract
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		11	6
Netting	[2]	0	0
Derivative Asset, Net		11	6
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Natural Gas Commodity Contract | Level 1
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0	0
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Natural Gas Commodity Contract | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		11	6
Fair Value Measured on a Recurring Basis | Other Current Assets | Other Derivative Instruments | Natural Gas Commodity Contract | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		0	0
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		92	36
Netting	[2]	(65)	(20)
Derivative Asset, Net		27	16
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Level 1
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		10	1
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		28	27
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		54	8
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Commodity Contract
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		92	36
Netting	[2]	(65)	(20)
Derivative Asset, Net		27	16
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Commodity Contract | Level 1
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		10	1
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Commodity Contract | Level 2
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		28	27
Fair Value Measured on a Recurring Basis | Other Noncurrent Assets | Other Derivative Instruments | Commodity Contract | Level 3
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross		54	8
Fair Value Measured on a Recurring Basis | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		115	60
Netting	[2]	(85)	(33)
Derivative Liability, Net		30	27
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 1
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		6	1
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 2
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		93	52
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Level 3
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		16	7
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Commodity Contract
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		112	54
Netting	[2]	(85)	(33)
Derivative Liability, Net		27	21
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Commodity Contract | Level 1
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		6	1
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Commodity Contract | Level 2
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		90	46
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Commodity Contract | Level 3
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		16	7
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Natural Gas Commodity Contract
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		3	6
Netting	[2]	0	0
Derivative Liability, Net		3	6
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Natural Gas Commodity Contract | Level 1
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0	0
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Natural Gas Commodity Contract | Level 2
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		3	6
Fair Value Measured on a Recurring Basis | Other Current Liabilities | Other Derivative Instruments | Natural Gas Commodity Contract | Level 3
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0	0
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		104	71
Netting	[2]	(75)	(20)
Derivative Liability, Net		29	51
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 1
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		3	1
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 2
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0	24
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Level 3
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		101	46
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Other Derivative Instruments | Commodity Contract
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		104	71
Netting	[2]	(75)	(20)
Derivative Liability, Net		29	51
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Other Derivative Instruments | Commodity Contract | Level 1
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		3	1
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Other Derivative Instruments | Commodity Contract | Level 2
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		0	24
Fair Value Measured on a Recurring Basis | Other Noncurrent Liabilities | Other Derivative Instruments | Commodity Contract | Level 3
Derivatives, Fair Value [Line Items]
Derivative Liability, Gross		$ 101	$ 46
[1]	Level 3 losses recognized in earnings are subject to offsetting gains of derivative instruments categorized as levels 1 and 2 in the income statement.
[2]	PSCo nets derivative instruments and related collateral on its consolidated balance sheet when supported by a legally enforceable master netting agreement, and all derivative instruments and related collateral amounts were subject to master netting agreements at Dec. 31, 2021 and 2020. At Dec. 31, 2021 and 2020, derivative assets and liabilities include no obligations to return cash collateral, respectively. At Dec. 31, 2021 and 2020, derivative assets and liabilities include rights to reclaim cash collateral of $14 million and $5 million, respectively. The counterparty netting amounts presented exclude settlement receivables and payables and non-derivative amounts that may be subject to the same master netting agreements.

Fair Value of Long-Term Debt (D

Fair Value of Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Long-term Debt, Gross	$ 6,467	$ 5,724
Level 2
Derivatives, Fair Value [Line Items]
Long-term debt, Fair Value	$ 7,291	$ 7,040

Benefit Plans and Other Postr_3

Benefit Plans and Other Postretirement Benefits, Pension Benefits (Details) - USD ($)		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019	Jan. 01, 2020	Jan. 01, 2019
Target Pension Asset Allocations [Abstract]
annual interest crediting rates			$ 2.26		$ 2.24		$ 3.11
Asset Transfers			0		0
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value			421,000,000	[1]	388,000,000	[2]
Fair value of plan assets			1,351,000,000	[1]	1,283,000,000	[2]		$ 1,283,000,000	$ 1,124,000,000
Pension Benefits [Abstract]
Total benefit obligation			1,363,000,000		1,428,000,000			$ 1,428,000,000	$ 1,330,000,000
Net benefit cost recognized for financial reporting			$ 30,000,000		$ 37,000,000		$ 38,000,000
Minimum number of years historical achieved weighted average annual returns used to determine investment return assumptions (in years)			20 years
Expected average long-term rate of return on assets (as a percent)			6.38%		6.84%		6.84%
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)			100.00%		100.00%
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	[3]		$ 0		$ 0		$ (3,000,000)
Pension Plan [Member] | PSCo [Member]
Target Pension Asset Allocations [Abstract]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement							$ (3,000,000)
Supplemental Executive Retirement Plan (SERP) and Nonqualified Pension Plan
Pension Benefits [Abstract]
Total benefit obligation			2,000,000		2,000,000
Xcel Energy Inc. | Supplemental Executive Retirement Plan (SERP) and Nonqualified Pension Plan
Pension Benefits [Abstract]
Total benefit obligation			43,000,000		43,000,000
Net benefit cost recognized for financial reporting			4,000,000		6,000,000
Equity Securities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value			0	[1]	0	[2]
Fair value of plan assets			$ 24,000,000	[1]	$ 27,000,000	[2]
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)			33.00%		35.00%
Long-Duration Fixed Income and Interest Rate Swap Securities [Member] | Pension Plan [Member]
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)			37.00%		35.00%
Short-to-intermediate fixed income securities [Member] | Pension Plan [Member]
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)			11.00%		13.00%
Alternative Investments [Member] | Pension Plan [Member]
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)			17.00%		15.00%
Cash | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value			$ 0	[1]	$ 0	[2]
Fair value of plan assets			$ 49,000,000	[1]	$ 75,000,000	[2]
Target Pension Asset Allocations [Abstract]
Target pension asset allocations (as a percent)			2.00%		2.00%
Subsequent Event | Pension Plan [Member]
Pension Benefits [Abstract]
Expected average long-term rate of return on assets for next fiscal year (as a percent)		6.39%
[1]	See Note 8 for further information on fair value measurement inputs and methods.
[2]	See Note 8 for further information on fair value measurement inputs and methods.
[3]	A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. In 2019, as a result of lump-sum distributions during the plan year, PSCo recorded a total pension settlement ch arge of $3 million. A

Benefit Plans and Other Postr_4

Benefit Plans and Other Postretirement Benefits, Fair Value of Pension Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019	Jan. 01, 2020	Jan. 01, 2019
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Liability, Defined Benefit Plan, Noncurrent	$ (23)		$ (161)
Pension Plan [Member]
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	1,351	[1]	1,283	[2]		$ 1,283	$ 1,124
Plan assets at net asset value	(421)	[1]	(388)	[2]
Service cost	32		30		$ 26
Interest cost	39		46		52
Plan amendments	0		0
Actuarial (gain) loss	(57)		102
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant	0		0
Medicare subsidy reimbursements	0		0
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(79)		(80)
Total benefit obligation	1,363		1,428			1,428	1,330
Actual return (loss) on plan assets	102		189
Employer contributions	45		50
Plan participants' contributions	0		0
Defined Benefit Plan, Plan Assets, Benefits Paid	(79)		(80)
Assets for Plan Benefits, Defined Benefit Plan	(6)		0
Liability, Defined Benefit Plan, Noncurrent	(18)		(145)
Pension Plan [Member] | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	565	[1]	622	[2]
Pension Plan [Member] | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	363	[1]	272	[2]
Pension Plan [Member] | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	2	[1]	1	[2]
Pension Plan [Member] | Cash
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	49	[1]	75	[2]
Plan assets at net asset value	0	[1]	0	[2]
Pension Plan [Member] | Cash | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	49	[1]	75	[2]
Pension Plan [Member] | Cash | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Pension Plan [Member] | Cash | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Pension Plan [Member] | Commingled funds
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	901	[1]	906	[2]
Plan assets at net asset value	(409)	[1]	(388)	[2]
Pension Plan [Member] | Commingled funds | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	492	[1]	518	[2]
Pension Plan [Member] | Commingled funds | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Pension Plan [Member] | Commingled funds | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Pension Plan [Member] | Debt Securities
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	362	[1]	271	[2]
Plan assets at net asset value	0	[1]	0	[2]
Pension Plan [Member] | Debt Securities | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Pension Plan [Member] | Debt Securities | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	360	[1]	270	[2]
Pension Plan [Member] | Debt Securities | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	2	[1]	1	[2]
Pension Plan [Member] | Equity Securities [Member]
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	24	[1]	27	[2]
Plan assets at net asset value	0	[1]	0	[2]
Pension Plan [Member] | Equity Securities [Member] | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	24	[1]	27	[2]
Pension Plan [Member] | Equity Securities [Member] | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Pension Plan [Member] | Equity Securities [Member] | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Pension Plan [Member] | Other
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	15	[1]	4	[2]
Plan assets at net asset value	12	[1]	0	[2]
Pension Plan [Member] | Other | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	2	[2]
Pension Plan [Member] | Other | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	3	[1]	2	[2]
Pension Plan [Member] | Other | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Other Postretirement Benefits Plan [Member]
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	393	[2]	404	[1]		404	401
Plan assets at net asset value	(68)	[2]	(61)	[1]
Service cost	1		1		1
Interest cost	11		13		$ 15
Plan amendments	0		0
Actuarial (gain) loss	(31)		52
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant	7		6
Medicare subsidy reimbursements	2		1
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(36)		(38)
Total benefit obligation	369		415			$ 415	$ 380
Actual return (loss) on plan assets	15		32
Employer contributions	3		3
Plan participants' contributions	7		6
Defined Benefit Plan, Plan Assets, Benefits Paid	(36)		(38)
Assets for Plan Benefits, Defined Benefit Plan	(24)		0
Liability, Defined Benefit Plan, Noncurrent	0		11
Other Postretirement Benefits Plan [Member] | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	82	[2]	88	[1]
Other Postretirement Benefits Plan [Member] | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	242	[2]	255	[1]
Other Postretirement Benefits Plan [Member] | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	1	[2]	0	[1]
Other Postretirement Benefits Plan [Member] | Cash
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	25	[2]	24	[1]
Plan assets at net asset value	0	[2]	0	[1]
Other Postretirement Benefits Plan [Member] | Cash | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	25	[2]	24	[1]
Other Postretirement Benefits Plan [Member] | Cash | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[2]	0	[1]
Other Postretirement Benefits Plan [Member] | Cash | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[2]	0	[1]
Other Postretirement Benefits Plan [Member] | Commingled funds
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	125	[2]	125	[1]
Plan assets at net asset value	(68)	[2]	(61)	[1]
Other Postretirement Benefits Plan [Member] | Commingled funds | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	57	[2]	64	[1]
Other Postretirement Benefits Plan [Member] | Commingled funds | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[2]	0	[1]
Other Postretirement Benefits Plan [Member] | Commingled funds | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[2]	0	[1]
Other Postretirement Benefits Plan [Member] | Debt Securities
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	195	[2]	207	[1]
Plan assets at net asset value	0	[2]	0	[1]
Other Postretirement Benefits Plan [Member] | Debt Securities | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[2]	0	[1]
Other Postretirement Benefits Plan [Member] | Debt Securities | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	194	[2]	207	[1]
Other Postretirement Benefits Plan [Member] | Debt Securities | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	1	[2]	0	[1]
Other Postretirement Benefits Plan [Member] | Other
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	2	[2]	3	[1]
Plan assets at net asset value	0	[2]	0	[1]
Other Postretirement Benefits Plan [Member] | Other | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[2]	0	[1]
Other Postretirement Benefits Plan [Member] | Other | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	2	[2]	3	[1]
Other Postretirement Benefits Plan [Member] | Other | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	$ 0	[2]	$ 0	[1]
[1]	See Note 8 for further information on fair value measurement inputs and methods.
[2]	See Note 8 for further information on fair value measurement inputs and methods.

Benefit Plans and Other Postr_5

Benefit Plans and Other Postretirement Benefits, Pension Plan Benefit Obligations, Cash Flows and Benefit Costs (Details) $ in Millions		1 Months Ended		12 Months Ended
		Jan. 31, 2022USD ($)		Dec. 31, 2022USD ($)		Dec. 31, 2021USD ($)Plan		Dec. 31, 2020USD ($)		Dec. 31, 2019USD ($)
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses						$ 831		$ 811		$ 810
Significant Assumptions Used to Measure Costs [Abstract]
Liability, Defined Benefit Plan, Noncurrent						23		161
Other Pension, Postretirement and Supplemental Plans [Member]
Change in Projected Benefit Obligation [Roll Forward]
Obligation at Jan. 1		$ 2		$ 2		2
Obligation at Dec. 31						2		2
Other Pension, Postretirement and Supplemental Plans [Member] | Xcel Energy Inc.
Change in Projected Benefit Obligation [Roll Forward]
Obligation at Jan. 1		43		43		43
Obligation at Dec. 31						43		43
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Net benefit cost recognized for financial reporting						4		6
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation at Dec. 31						1,291		1,353
Change in Projected Benefit Obligation [Roll Forward]
Obligation at Jan. 1		1,363		1,363		1,428
Service cost						32		30		26
Interest cost						39		46		52
Plan amendments						0		0
Actuarial (gain) loss						(57)		102
Benefit payments						(79)		(80)
Obligation at Dec. 31						1,363		1,428
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1		1,351	[1]	$ 1,351	[1]	1,283	[2]
Actual return (loss) on plan assets						102		189
Employer contributions						45		50
Plan participants' contributions						0		0
Benefit payments						(79)		(80)
Fair value of plan assets at Dec. 31						1,351	[1]	1,283	[2]
Funded Status of Plans at Dec. 31 [Abstract]
Funded status						12		145
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost [Abstract]
Net loss						313		432
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax						(1)		(1)
Total						312		431
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates [Abstract]
Current regulatory assets						24		25
Noncurrent regulatory assets						288		404
Deferred income taxes						0		1
Net-of-tax accumulated OCI						0		1
Total						$ 312		$ 431
Significant Assumptions Used to Measure Benefit Obligations [Abstract]
Discount rate for year-end valuation (as a percent)						3.08%		2.71%
Expected average long-term increase in compensation level (as a percent)						3.75%		3.75%
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service cost						$ 32		$ 30		26
Interest cost						39		46		52
Expected return on plan assets						(73)		(70)		(69)
Amortization of prior service (credit) cost						0		(3)		(3)
Amortization of net loss						32		30		25
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	[3]					0		0		(3)
Net periodic pension cost						30		33		34
Defined Benefit Plan, Costs Not Recognized Due To Regulation						0		4		4
Net benefit cost recognized for financial reporting						$ 30		$ 37		$ 38
Significant Assumptions Used to Measure Costs [Abstract]
Discount rate (as a percent)						2.71%		3.49%		4.31%
Expected average long-term increase in compensation level (as a percent)						3.75%		3.75%		3.75%
Expected average long-term rate of return on assets (as a percent)						6.38%		6.84%		6.84%
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant						$ 0		$ 0
Medicare subsidy reimbursements						0		0
Liability, Defined Benefit Plan, Noncurrent						18		145
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position						(12)		(145)
Pension Plan [Member] | PSCo [Member]
Cash Flows [Abstract]
Total contributions to Xcel Energy's pension plans during the period						$ 46		$ 50		$ 46
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement										$ (3)
Pension Plan [Member] | Xcel Energy Inc.
Cash Flows [Abstract]
Number of pension plans to which contributions were made | Plan						4
Pension Plan [Member] | Subsequent Event
Significant Assumptions Used to Measure Costs [Abstract]
Expected average long-term rate of return on assets for next fiscal year (as a percent)				6.39%
Pension Plan [Member] | Subsequent Event | PSCo [Member]
Cash Flows [Abstract]
Total contributions to Xcel Energy's pension plans during the period		$ 40
[1]	See Note 8 for further information on fair value measurement inputs and methods.
[2]	See Note 8 for further information on fair value measurement inputs and methods.
[3]	A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. In 2019, as a result of lump-sum distributions during the plan year, PSCo recorded a total pension settlement ch arge of $3 million. A

Benefit Plans and Other Postr_6

Benefit Plans and Other Postretirement Benefits, Postretirement Health Care Benefits (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Other Postretirement Benefits Plan [Member]
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	100.00%	100.00%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.09%	2.65%
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Pre-65	5.30%	5.50%
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Post-65	4.90%	5.00%
Ultimate health care trend assumption rate (as a percent)	4.50%	4.50%
Other Postretirement Benefits Plan [Member] | Domestic and international equity securities
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	15.00%	15.00%
Other Postretirement Benefits Plan [Member] | Long-Duration Fixed Income and Interest Rate Swap Securities [Member]
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	0.00%	0.00%
Other Postretirement Benefits Plan [Member] | Short-to-intermediate fixed income securities
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	71.00%	72.00%
Other Postretirement Benefits Plan [Member] | Alternative investments
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	8.00%	9.00%
Other Postretirement Benefits Plan [Member] | Cash
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	6.00%	4.00%
Pension Plan [Member]
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	100.00%	100.00%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.08%	2.71%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	3.75%	3.75%
Pension Plan [Member] | Domestic and international equity securities
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	33.00%	35.00%
Pension Plan [Member] | Long-Duration Fixed Income and Interest Rate Swap Securities [Member]
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	37.00%	35.00%
Pension Plan [Member] | Short-to-intermediate fixed income securities
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	11.00%	13.00%
Pension Plan [Member] | Alternative investments
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	17.00%	15.00%
Pension Plan [Member] | Cash
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	2.00%	2.00%

Benefit Plans and Other Postr_7

Benefit Plans and Other Postretirement Benefits, Fair Value of Postretirement Benefit Plan Assets (Details) - Other Postretirement Benefits Plan [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019	Jan. 01, 2020	Jan. 01, 2019
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	$ 393	[1]	$ 404	[2]		$ 404	$ 401
Plan assets at net asset value	68	[1]	61	[2]
Service cost	1		1		$ 1
Service cost			0
Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	82	[1]	88	[2]
Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	242	[1]	255	[2]
Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	1	[1]	0	[2]
Debt Securities
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	195	[1]	207	[2]
Plan assets at net asset value	0	[1]	0	[2]
Debt Securities | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Debt Securities | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	194	[1]	207	[2]
Debt Securities | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	1	[1]	0	[2]
Cash
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	25	[1]	24	[2]
Plan assets at net asset value	0	[1]	0	[2]
Cash | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	25	[1]	24	[2]
Cash | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Cash | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Insurance contracts
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	46	[1]	45	[2]
Plan assets at net asset value	0	[1]	0	[2]
Insurance contracts | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Insurance contracts | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	46	[1]	45	[2]
Insurance contracts | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Other
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	2	[1]	3	[2]
Plan assets at net asset value	0	[1]	0	[2]
Other | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Other | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	2	[1]	3	[2]
Other | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Commingled funds
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	125	[1]	125	[2]
Plan assets at net asset value	68	[1]	61	[2]
Commingled funds | Level 1
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	57	[1]	64	[2]
Commingled funds | Level 2
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	0	[1]	0	[2]
Commingled funds | Level 3
Plan Assets Measured at Fair Value for Each of the Fair Value Hierarchy Levels [Abstract]
Fair value of plan assets	$ 0	[1]	$ 0	[2]
[1]	See Note 8 for further information on fair value measurement inputs and methods.
[2]	See Note 8 for further information on fair value measurement inputs and methods.

Benefit Plans and Other Postr_8

Benefit Plans and Other Postretirement Benefits, Postretirement Benefit Plan Benefit Obligations, Cash Flows and Benefit Costs (Details) - USD ($)		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Significant Assumptions Used to Measure Costs [Abstract]
Liability, Defined Benefit Plan, Noncurrent		$ 23,000,000		$ 161,000,000
Defined Contribution Plan, Administrative Expense		12,000,000		12,000,000		$ 11,000,000
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value		68,000,000	[1]	61,000,000	[2]
Plan amendments		0		0
Change in Projected Benefit Obligation [Roll Forward]
Obligation at Jan. 1		415,000,000
Service cost		1,000,000		1,000,000		1,000,000
Interest cost		11,000,000		13,000,000		15,000,000
Medicare subsidy reimbursements		2,000,000		1,000,000
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant		7,000,000		6,000,000
Actuarial (gain) loss		(31,000,000)		52,000,000
Benefit payments		(36,000,000)		(38,000,000)
Obligation at Dec. 31		369,000,000		415,000,000
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	[2]	404,000,000
Actual return (loss) on plan assets		15,000,000		32,000,000
Plan participants' contributions		7,000,000		6,000,000
Employer contributions		3,000,000		3,000,000
Benefit payments		(36,000,000)		(38,000,000)
Fair value of plan assets at Dec. 31		393,000,000	[1]	404,000,000	[2]
Funded Status of Plans at Dec. 31 [Abstract]
Funded status		24,000,000		(11,000,000)
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost [Abstract]
Net loss		48,000,000		81,000,000
Prior service (credit) cost		2,000,000		6,000,000
Total		46,000,000		75,000,000
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates [Abstract]
Noncurrent regulatory assets		$ 46,000,000		$ 75,000,000
Significant Assumptions Used to Measure Benefit Obligations [Abstract]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Pre-65		5.30%		5.50%
Ultimate health care trend assumption rate (as a percent)		4.50%		4.50%
Period until ultimate trend rate is reached (in years)		4		5
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		$ 1,000,000		$ 1,000,000		1,000,000
Interest cost		11,000,000		13,000,000		15,000,000
Expected return on plan assets		(16,000,000)		(17,000,000)		(19,000,000)
Amortization of prior service (credit) cost		(4,000,000)		(4,000,000)		(5,000,000)
Amortization of net loss		3,000,000		1,000,000		3,000,000
Net periodic pension cost		$ (5,000,000)		$ (7,000,000)		$ (5,000,000)
Significant Assumptions Used to Measure Costs [Abstract]
Discount rate (as a percent)		2.65%		3.47%		4.32%
Expected average long-term rate of return on assets (as a percent)		4.10%		4.50%		4.50%
Liability, Defined Benefit Plan, Noncurrent		$ 0		$ (11,000,000)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position		$ 24,000,000		$ (11,000,000)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.09%		2.65%
Amounts Not Yet Recognized As Components Of Net Periodic Benefit Cost Recorded As Current Regulatory Assets		$ 0		$ 0
Deferred Income Taxes		0		0
Amounts Not Yet Recognized As Components Of Net Periodic Benefit Cost Recorded As Net-Of-Tax Accumulated Other Comprehensive Income		0		0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	[3]	0		0		$ 0
Defined Benefit Plan, Costs Not Recognized Due To Regulation		2,000,000		3,000,000		1,000,000
Net benefit cost recognized for financial reporting		$ (3,000,000)		$ (4,000,000)		(4,000,000)
Target pension asset allocations (as a percent)		100.00%		100.00%
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months		$ 30,000,000
Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, Next Twelve Months		2,000,000
Defined Benefit Plan Net Projected Benefit Payments In Year One		28,000,000
Defined Benefit Plan, Expected Future Benefit Payment, Year Two		29,000,000
Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, Year Two		2,000,000
Defined Benefit Plan Net Projected Benefit Payments In Year Two		27,000,000
Defined Benefit Plan, Expected Future Benefit Payment, Year Three		29,000,000
Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, Year Three		2,000,000
Defined Benefit Plan Net Projected Benefit Payments In Year Three		27,000,000
Defined Benefit Plan, Expected Future Benefit Payment, Year Four		28,000,000
Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, Year Four		2,000,000
Defined Benefit Plan Net Projected Benefit Payments In Year Four		26,000,000
Defined Benefit Plan, Expected Future Benefit Payment, Year Five		27,000,000
Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, Year Five		2,000,000
Defined Benefit Plan Net Projected Benefit Payments In Year Five		25,000,000
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter		123,000,000
Defined Benefit Plan, Expected Future Prescription Drug Subsidy Receipt, after Year Five		13,000,000
Defined Benefit Plan Net Projected Benefit Payments In Five Fiscal Years Thereafter		$ 110,000,000
Other Postretirement Benefits Plan [Member] | Domestic and international equity securities
Significant Assumptions Used to Measure Costs [Abstract]
Target pension asset allocations (as a percent)		15.00%		15.00%
Other Postretirement Benefits Plan [Member] | Long-Duration Fixed Income and Interest Rate Swap Securities [Member]
Significant Assumptions Used to Measure Costs [Abstract]
Target pension asset allocations (as a percent)		0.00%		0.00%
Other Postretirement Benefits Plan [Member] | Short-to-intermediate fixed income securities
Significant Assumptions Used to Measure Costs [Abstract]
Target pension asset allocations (as a percent)		71.00%		72.00%
Other Postretirement Benefits Plan [Member] | Alternative investments
Significant Assumptions Used to Measure Costs [Abstract]
Target pension asset allocations (as a percent)		8.00%		9.00%
Other Postretirement Benefits Plan [Member] | Cash
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value		$ 0	[1]	$ 0	[2]
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	[2]	24,000,000
Fair value of plan assets at Dec. 31		$ 25,000,000	[1]	$ 24,000,000	[2]
Significant Assumptions Used to Measure Costs [Abstract]
Target pension asset allocations (as a percent)		6.00%		4.00%
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value		$ 421,000,000	[2]	$ 388,000,000	[1]
Plan amendments		0		0
Change in Projected Benefit Obligation [Roll Forward]
Obligation at Jan. 1		1,428,000,000
Service cost		32,000,000		30,000,000		26,000,000
Interest cost		39,000,000		46,000,000		52,000,000
Medicare subsidy reimbursements		0		0
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant		0		0
Actuarial (gain) loss		(57,000,000)		102,000,000
Benefit payments		(79,000,000)		(80,000,000)
Obligation at Dec. 31		1,363,000,000		1,428,000,000
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	[1]	1,283,000,000
Actual return (loss) on plan assets		102,000,000		189,000,000
Plan participants' contributions		0		0
Employer contributions		45,000,000		50,000,000
Benefit payments		(79,000,000)		(80,000,000)
Fair value of plan assets at Dec. 31		1,351,000,000	[2]	1,283,000,000	[1]
Funded Status of Plans at Dec. 31 [Abstract]
Funded status		(12,000,000)		(145,000,000)
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost [Abstract]
Net loss		313,000,000		432,000,000
Prior service (credit) cost		1,000,000		1,000,000
Total		312,000,000		431,000,000
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates [Abstract]
Noncurrent regulatory assets		288,000,000		404,000,000
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		32,000,000		30,000,000		26,000,000
Interest cost		39,000,000		46,000,000		52,000,000
Expected return on plan assets		(73,000,000)		(70,000,000)		(69,000,000)
Amortization of prior service (credit) cost		0		(3,000,000)		(3,000,000)
Amortization of net loss		32,000,000		30,000,000		25,000,000
Net periodic pension cost		$ 30,000,000		$ 33,000,000		$ 34,000,000
Significant Assumptions Used to Measure Costs [Abstract]
Discount rate (as a percent)		2.71%		3.49%		4.31%
Expected average long-term rate of return on assets (as a percent)		6.38%		6.84%		6.84%
Liability, Defined Benefit Plan, Noncurrent		$ 18,000,000		$ 145,000,000
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position		$ (12,000,000)		$ (145,000,000)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.08%		2.71%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase		3.75%		3.75%
Amounts Not Yet Recognized As Components Of Net Periodic Benefit Cost Recorded As Current Regulatory Assets		$ 24,000,000		$ 25,000,000
Deferred Income Taxes		0		1,000,000
Amounts Not Yet Recognized As Components Of Net Periodic Benefit Cost Recorded As Net-Of-Tax Accumulated Other Comprehensive Income		0		1,000,000
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	[3]	0		0		$ 3,000,000
Defined Benefit Plan, Costs Not Recognized Due To Regulation		0		4,000,000		4,000,000
Net benefit cost recognized for financial reporting		$ 30,000,000		$ 37,000,000		$ 38,000,000
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase		3.75%		3.75%		3.75%
Target pension asset allocations (as a percent)		100.00%		100.00%
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months		$ 83,000,000
Defined Benefit Plan, Expected Future Benefit Payment, Year Two		82,000,000
Defined Benefit Plan, Expected Future Benefit Payment, Year Three		82,000,000
Defined Benefit Plan, Expected Future Benefit Payment, Year Four		82,000,000
Defined Benefit Plan, Expected Future Benefit Payment, Year Five		81,000,000
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter		388,000,000
Pension Plan [Member] | Domestic and international equity securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value		0	[2]	$ 0	[1]
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	[1]	27,000,000
Fair value of plan assets at Dec. 31		$ 24,000,000	[2]	$ 27,000,000	[1]
Significant Assumptions Used to Measure Costs [Abstract]
Target pension asset allocations (as a percent)		33.00%		35.00%
Pension Plan [Member] | Long-Duration Fixed Income and Interest Rate Swap Securities [Member]
Significant Assumptions Used to Measure Costs [Abstract]
Target pension asset allocations (as a percent)		37.00%		35.00%
Pension Plan [Member] | Short-to-intermediate fixed income securities
Significant Assumptions Used to Measure Costs [Abstract]
Target pension asset allocations (as a percent)		11.00%		13.00%
Pension Plan [Member] | Alternative investments
Significant Assumptions Used to Measure Costs [Abstract]
Target pension asset allocations (as a percent)		17.00%		15.00%
Pension Plan [Member] | Cash
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value		$ 0	[2]	$ 0	[1]
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	[1]	75,000,000
Fair value of plan assets at Dec. 31		$ 49,000,000	[2]	$ 75,000,000	[1]
Significant Assumptions Used to Measure Costs [Abstract]
Target pension asset allocations (as a percent)		2.00%		2.00%
[1]	See Note 8 for further information on fair value measurement inputs and methods.
[2]	See Note 8 for further information on fair value measurement inputs and methods.
[3]	A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. In 2019, as a result of lump-sum distributions during the plan year, PSCo recorded a total pension settlement ch arge of $3 million. A

Benefit Plans and Other Postr_9

Benefit Plans and Other Postretirement Benefits, Projected Benefit Payments (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Defined Contribution Plan, Administrative Expense		$ 12	$ 12	$ 11
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Gross Projected Benefit Payments [Abstract]
2022		30
2023		29
2024		29
2025		28
2026		27
2027-2031		123
Expected Medicare Part D Subsidies [Abstract]
2022		2
2023		2
2024		2
2025		2
2026		2
2027-2031		13
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
2020		28
2021		27
2022		27
2023		26
2024		25
2025-2029		110
Pension Plan [Member]
Defined Benefit Plan, Gross Projected Benefit Payments [Abstract]
2022		83
2023		82
2024		82
2025		82
2026		81
2027-2031		388
Pension Plan [Member] | Xcel Energy [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Total contributions to Xcel Energy's pension plans during the period		131	150	154
Pension Plan [Member] | Xcel Energy [Member] | Subsequent Event
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Total contributions to Xcel Energy's pension plans during the period	$ 50
Pension Plan [Member] | PSCo [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Total contributions to Xcel Energy's pension plans during the period		46	50	46
Pension Plan [Member] | PSCo [Member] | Subsequent Event
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Total contributions to Xcel Energy's pension plans during the period	40
Defined Benefit Plan, Overfunded Plan [Member] | Xcel Energy [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Total contributions to Xcel Energy's pension plans during the period		15	11	15
Defined Benefit Plan, Overfunded Plan [Member] | Xcel Energy [Member] | Subsequent Event
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Total contributions to Xcel Energy's pension plans during the period	$ 9
Defined Benefit Plan, Overfunded Plan [Member] | PSCo [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Total contributions to Xcel Energy's pension plans during the period		$ 3	$ 3	$ 4

Benefit Plans and Other Post_10

Benefit Plans and Other Postretirement Benefits Plan Amendments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Administrative Expense	$ 12	$ 12	$ 11
plan amendments		$ 0	$ 0

Commitments and Contingencies G

Commitments and Contingencies Gas Trading Litigation (Details)	12 Months Ended
	Dec. 31, 2021USD ($)
Public Utilities, General Disclosures [Line Items]
Active Cases	$ 1
Breckenridge Litigation [Domain]	$ 3,000,000
Commitments and Contingencies Disclosure [Text Block]	AROs — AROs have been recorded for PSCo’s assets. PSCo’s AROs were as follows: 2021 (Millions Jan. 1, Accretion Cash Flow Revisions (a) Dec. 31, 2021 (b) Electric Steam, hydro and other production $ 137 $ 5 $ 10 $ 152 Wind 40 2 — 42 Distribution 15 1 — 16 Natural gas Transmission and distribution 203 9 (8) 204 Miscellaneous 3 — 5 8 Common Miscellaneous 1 (1) — — Total liability $ 399 $ 16 $ 7 $ 422 (a) In 2021, AROs were revised for changes in timing and estimates of cash flows. Revisions in steam, hydro, and other production AROs primarily related to changes in cost estimates for remediation of ash containment facilities. Changes in gas transmission and distribution AROs were primarily related to changes in labor rates coupled with increased gas line mileage and number of services. (b) There were no ARO amounts incurred or settled in 2021. 2020 (Millions Jan. 1, 2020 Amounts Incurred (a) Amounts Settled (b) Accretion Cash Flow Revisions (c) Dec. 31, 2020 Electric Steam, hydro and other production $ 100 $ — $ — $ 4 $ 33 $ 137 Wind 16 26 (3) 1 — 40 Distribution 14 — — 1 — 15 Natural gas Transmission and distribution 190 — — 8 5 203 Miscellaneous 3 — — — — 3 Common Miscellaneous 1 — — — — 1 Total liability $ 324 $ 26 $ (3) $ 14 $ 38 $ 399 (a) Amounts incurred related to the Cheyenne Ridge wind farm placed in service in 2020. (b) Amounts settled related to removal of wind facilities. (c) In 2020, AROs were revised for changes in timing and estimates of cash flows. Revisions in steam, hydro, and other production AROs primarily related to changes in cost estimates for remediation of ash containment facilities. Indeterminate AROs — Outside of the recorded asbestos AROs, other plants or buildings may contain asbestos due to the age of many of PSCo’s facilities, but no confirmation or measurement of the cost of removal could be determined as of Dec. 31, 2021. Therefore, an ARO has not been recorded for these facilities. Leases PSCo evaluates contracts that may contain leases, including PPAs and arrangements for the use of office space and other facilities, vehicles and equipment. A contract contains a lease if it conveys the exclusive right to control the use of a specific asset. A contract determined to contain a lease is evaluated further to determine if the arrangement is a finance lease. ROU assets represent PSCo's rights to use leased assets. The present value of future operating lease payments is recognized in current and noncurrent operating lease liabilities. These amounts, adjusted for any prepayments or incentives, are recognized as operating lease ROU assets. Most of PSCo’s leases do not contain a readily determinable discount rate. Therefore, the present value of future lease payments is generally calculated using the estimated incremental borrowing rate (weighted average of 3.9%). PSCo has elected to utilize the practical expedient under which non-lease components, such as asset maintenance costs included in payments, are not deducted from minimum lease payments for the purposes of lease accounting and disclosure. Leases with an initial term of 12 months or less are classified as short-term leases and are not recognized on the consolidated balance sheet. Operating lease ROU assets: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 PPAs $ 600 $ 591 Other 77 68 Gross operating lease ROU assets 677 659 Accumulated amortization (268) (159) Net operating lease ROU assets $ 409 $ 500 ROU assets for finance leases are included in other noncurrent assets, and the present value of future finance lease payments is included in other current liabilities and other noncurrent liabilities. PSCo’s most significant finance lease activities are related to WYCO, a joint venture with CIG, to develop and lease natural gas pipeline, storage and compression facilities. Xcel Energy Inc. has a 50% ownership interest in WYCO. WYCO leases its facilities to CIG, and CIG operates the facilities, providing natural gas storage and transportation services to PSCo under separate service agreements. PSCo accounts for its Totem natural gas storage service and Front Range pipeline arrangements with CIG and WYCO, respectively, as finance leases. Finance lease ROU assets: (Millions of Dollars) Dec. 31, 2021 Dec. 31, 2020 Gas storage facilities $ 201 $ 201 Gas pipeline 21 21 Gross finance lease ROU assets 222 222 Accumulated amortization (97) (90) Net finance lease ROU assets $ 125 $ 132 Components of lease expense: (Millions of Dollars) 2021 2020 2019 Operating leases PPA capacity payments $ 102 $ 100 $ 98 Other operating leases (a) 16 13 14 Total operating lease expense (b) $ 118 $ 113 $ 112 Finance leases Amortization of ROU assets $ 7 $ 7 $ 6 Interest expense on lease liability 17 18 19 Total finance lease expense $ 24 $ 25 $ 25 (a) Includes short-term lease expense of $1 million , $1 million and $2 million for 2021, 2020 and 2019, respectively. (b) PPA capacity payments are included in electric fuel and purchased power on the consolidated statements of income. Expense for other operating leases is included in O&M expense and electric fuel and purchased power. Commitments under operating and finance leases as of Dec. 31, 2021: (Millions of Dollars) PPA (a) (b) Operating Leases Other Operating Leases Total Leases Finance Leases 2022 $ 84 $ 16 $ 100 $ 21 2023 70 11 81 20 2024 63 11 74 20 2025 63 5 68 19 2026 59 1 60 18 Thereafter 104 11 115 362 Total minimum obligation 443 55 498 460 Interest component of obligation (57) (6) (63) (335) Present value of minimum obligation $ 386 $ 49 435 125 Less current portion (84) (4) Noncurrent operating and finance lease liabilities $ 351 $ 121 Weighted-average remaining lease term in years 6.5 37.3 (a) Amounts do not include PPAs accounted for as executory contracts and/or contingent payments, such as energy payments on renewable PPAs. (b) PPA operating leases contractually expire at various dates through 2032. Non-Lease PPAs — SPS has entered into PPAs with other utilities and energy suppliers for purchased power to meet system load and energy requirements, operating reserve obligations and as part of wholesale and commodity trading activities. In general, these agreements provide for energy payments, based on actual energy delivered and capacity payments. Certain PPAs, accounted for as executory contracts with various expiration dates through 2027, contain minimum energy purchase requirements. Included in electric fuel and purchased power expenses for PPAs accounted for as executory contracts were payments for capacity of $2 million, $10 million and $12 million in 2021, 2020 and 2019, respectively. Capacity and energy payments are contingent on the IPP meeting contract obligations, including plant availability requirements. Certain contractual payments are adjusted based on market indices. The effects of price adjustments on financial results are mitigated through purchased energy cost recovery mechanisms. At Dec. 31, 2021, the estimated future payments for capacity that PSCo is obligated to purchase pursuant to these executory contracts, subject to availability, were as follows: (Millions of Dollars) Capacity 2022 $ 3 2023 3 2024 3 2025 3 2026 3 Thereafter 3 Total $ 18 Fuel Contracts — PSCo has entered into various long-term commitments for the purchase and delivery of a significant portion of its coal and natural gas requirements. These contracts expire between 2023 and 2060. PSCo is required to pay additional amounts depending on actual quantities shipped under these agreements. Estimated minimum purchases under these contracts as of Dec. 31, 2021: (Millions of Dollars) Coal Natural gas supply Natural gas storage and 2022 $ 186 $ 324 $ 116 2023 102 75 67 2024 67 3 37 2025 28 — 36 2026 29 — 35 Thereafter 30 — 440 Total $ 442 $ 402 $ 731 VIEs Under certain PPAs, PSCo purchases power from IPPs for which PSCo is required to reimburse fuel costs, or to participate in tolling arrangements under which PSCo procures the natural gas required to produce the energy that it purchases. PSCo has determined that certain IPPs are VIEs. PSCo is not subject to risk of loss from the operations of these entities, and no significant financial support is required other than contractual payments for energy and capacity.

Commitments and Contingencies M

Commitments and Contingencies MGP Sites (Details)	Dec. 31, 2021Site
Other MGP, Landfill, or Disposal Sites [Domain]
Loss Contingencies [Line Items]
Number of identified MGP, landfill, or disposal sites under current investigation and/or remediation	4

Commitments and Contingencies E

Commitments and Contingencies Environmental Requirements - Water and Waste (Details) - Federal Coal Ash Regulation [Domain] $ in Millions	Dec. 31, 2021USD ($)
Loss Contingencies [Line Items]
Number of regulated ash units that will still be in operation by the end of 2019	5
Number of sites where statistically significant increases over established groundwater standards exist	4
Number of sites where corrective action options are being evaluated for locations with statistically significant increases above background concentrations	2
Number of sites where monitoring results indicate potential offsite impacts to groundwater	1
Estimated cost to remediate groundwater sampling results	$ 35
Number of impoundments where closure plans will be expedited	1
Estimated cost of construction of an alternative collection and treatment system	$ 25
Estimated cost to close Comanche station bottom ash pond	$ 3

Commitments and Contingencies,

Commitments and Contingencies, Asset Retirement Obligations (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		$ 399		$ 324
Amounts Incurred		0		26	[1]
Amounts Settled		0		(3)	[2]
Accretion		16		14
Cash Flow Revisions		7	[3]	38	[4]
Ending balance		422	[5]	399
Electric Plant Steam and Other Production Ash Containment
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		137		100
Amounts Incurred	[1]			0
Amounts Settled	[2]			0
Accretion		5		4
Cash Flow Revisions		10	[3]	33	[4]
Ending balance		152	[5]	137
Electric Plant Wind Production
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		40		16
Amounts Incurred	[1]			26
Amounts Settled	[2]			(3)
Accretion		2		1
Cash Flow Revisions		0	[3]	0	[4]
Ending balance		42	[5]	40
Electric Plant Electric Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		15		14
Amounts Incurred	[1]			0
Amounts Settled	[2]			0
Accretion		1		1
Cash Flow Revisions		0	[3]	0	[4]
Ending balance		16	[5]	15
Natural Gas Plant Gas Transmission and Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		203		190
Amounts Incurred	[1]			0
Amounts Settled	[2]			0
Accretion		9		8
Cash Flow Revisions		(8)	[3]	5	[4]
Ending balance		204	[5]	203
Natural Gas Plant Other
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		3		3
Amounts Incurred	[1]			0
Amounts Settled	[2]			0
Accretion		0		0
Cash Flow Revisions		5	[3]	0	[4]
Ending balance		8	[5]	3
Common and Other Property Common Miscellaneous
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		1		1
Amounts Incurred	[1]			0
Amounts Settled	[2]			0
Accretion		(1)		0
Cash Flow Revisions		0	[3]	0	[4]
Ending balance		$ 0	[5]	$ 1
[1]	Amounts incurred related to the Cheyenne Ridge wind farm placed in service in 2020.
[2]	Amounts settled related to removal of wind facilities.
[3]	In 2021, AROs were revised for changes in timing and estimates of cash flows. Revisions in steam, hydro, and other production AROs primarily related to changes in cost estimates for remediation of ash containment facilities. Changes in gas transmission and distribution AROs were primarily related to changes in labor rates coupled with increased gas line mileage and number of services.
[4]	In 2020, AROs were revised for changes in timing and estimates of cash flows. Revisions in steam, hydro, and other production AROs primarily related to changes in cost estimates for remediation of ash containment facilities.
[5]	There were no ARO amounts incurred or settled in 2021.

Indeterminate AROs (Details)

Indeterminate AROs (Details) $ in Millions	Dec. 31, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
Indeterminate Costs Incurred, Asset Retirement Obligation Due to Asbestos	$ 0

Commitments and Contingencies_2

Commitments and Contingencies, Leases (Details) - USD ($)		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Maximum Length - Short-Term Leases		12 months
Operating Lease, Weighted Average Discount Rate, Percent		3.90%
Short-term Lease, Cost		$ 1,000,000	$ 1,000,000	$ 2,000,000
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		677,000,000	659,000,000
Operating Lease, Right-of-Use Asset, Accumulated Depreciation		(268,000,000)	(159,000,000)
Operating lease right-of-use assets		409,000,000	500,000,000
Finance Lease, Assets and Liabilities, Lessee [Abstract]
Finance Lease, Right-of-Use Asset, Gross		222,000,000	222,000,000
Finance Lease, Right-of-Use Asset, Accumulated Depreciation		(97,000,000)	(90,000,000)
Finance Lease, Right-of-Use Asset		125,000,000	132,000,000
Lease, Cost [Abstract]
Operating Lease, Cost	[1]	118,000,000	113,000,000	112,000,000
Finance Lease, Right-of-Use Asset, Amortization		7,000,000	7,000,000	6,000,000
Finance Lease, Interest Expense		17,000,000	18,000,000	19,000,000
Finance Lease, Cost		24,000,000	25,000,000	25,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022		100,000,000
2023		81,000,000
2024		74,000,000
2025		68,000,000
2026		60,000,000
Thereafter		115,000,000
Total minimum obligation		498,000,000
Interest component of obligation		(63,000,000)
Operating lease liabilities		435,000,000
Less current portion		(84,000,000)	(97,000,000)
Operating lease liabilities		351,000,000	432,000,000
Weighted Average Remaining lease term, operating		6.5
Weighted Average Remaining lease term, finance		37.3
Lessee, Finance Lease, Description [Abstract]
2022		21,000,000
2023		20,000,000
2024		20,000,000
2025		19,000,000
2026		18,000,000
Thereafter		362,000,000
Total minimum obligation		460,000,000
Interest component of obligation		(335,000,000)
Present value of minimum obligation		125,000,000
Less current portion		(4,000,000)
Noncurrent operating and finance lease liabilities		121,000,000
Property, Plant and Equipment, Other Types [Member]
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		77,000,000	68,000,000
Lease, Cost [Abstract]
Operating Lease, Cost	[2]	16,000,000	13,000,000	14,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022		16,000,000
2023		11,000,000
2024		11,000,000
2025		5,000,000
2026		1,000,000
Thereafter		11,000,000
Total minimum obligation		55,000,000
Interest component of obligation		(6,000,000)
Operating lease liabilities		49,000,000
Gas Storage Facilities [Member]
Finance Lease, Assets and Liabilities, Lessee [Abstract]
Finance Lease, Right-of-Use Asset, Gross		201,000,000	201,000,000
Gas Pipeline
Finance Lease, Assets and Liabilities, Lessee [Abstract]
Finance Lease, Right-of-Use Asset, Gross		21,000,000	21,000,000
Purchased Power Agreements
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		600,000,000	591,000,000
Lease, Cost [Abstract]
Operating Lease, Cost		102,000,000	$ 100,000,000	$ 98,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022	[3],[4]	84,000,000
2023	[3],[4]	70,000,000
2024	[3],[4]	63,000,000
2025	[3],[4]	63,000,000
2026	[3],[4]	59,000,000
Thereafter	[3],[4]	104,000,000
Total minimum obligation	[3],[4]	443,000,000
Interest component of obligation	[3],[4]	(57,000,000)
Operating lease liabilities	[3],[4]	$ 386,000,000
WYCO, Inc. [Member]
Lessee, Finance Lease, Description [Abstract]
Equity Method Investment, Ownership Percentage		50.00%
[1]	PPA capacity payments are included in electric fuel and purchased power on the consolidated statements of income. Expense for other operating leases is included in O&M expense and electric fuel and purchased power.
[2]	Includes short-term lease expense of $1 million , $1 million and $2 million for 2021, 2020 and 2019, respectively.
[3]	Amounts do not include PPAs accounted for as executory contracts and/or contingent payments, such as energy payments on renewable PPAs.
[4]	PPA operating leases contractually expire at various dates through 2032.

Commitments and Contingencies_3

Commitments and Contingencies, Purchased Power Agreements (Details) - Capacity - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Purchased Power Agreements (PPAs) [Abstract]
Payments for capacity	$ 2	$ 10	$ 12
Estimated Future Payments Under PPAs [Abstract]
2022	3
2023	3
2024	3
2025	3
2026	3
Thereafter	3
Total	$ 18

Commitments and Contingencies_4

Commitments and Contingencies, Fuel Contracts (Details) $ in Millions	Dec. 31, 2021USD ($)
Coal
2022	$ 186
2023	102
2024	67
2025	28
2026	29
Thereafter	30
Total	442
Natural Gas Supply
2022	324
2023	75
2024	3
2025	0
2026	0
Thereafter	0
Total	402
Natural Gas Storage and Transportation
2022	116
2023	67
2024	37
2025	36
2026	35
Thereafter	440
Total	$ 731

Commitments and Contingencies_5

Commitments and Contingencies, Variable Interest Entities (Details) - MW	Dec. 31, 2021	Dec. 31, 2020
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Purchased Power Agreements (PPAs) [Abstract]
Generating capacity (in MW)	1,518	1,518

Other Comprehensive Income (Det

Other Comprehensive Income (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive loss at beginning of period		$ 7,592
Total income tax expense		33		$ 45		$ 80
Accumulated other comprehensive loss at end of period		8,444		7,592
Gains and Losses on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive loss at beginning of period		(23)		(24)
Amortization of net actuarial income (loss)		(1)		0
Net current period other comprehensive income (loss)		2		1
Accumulated other comprehensive loss at end of period		(21)		(23)		(24)
Gains and Losses on Cash Flow Hedges | Reclassification out of Accumulated Other Comprehensive Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total income tax expense		0		0
Reclassification from AOCI, Current Period, Tax		0		0
Gains and Losses on Cash Flow Hedges | Interest Rate Swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amortization of net actuarial income (loss)		(1)	[1]	(1)	[2]
Defined Benefit Pension and Postretirement Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive loss at beginning of period		(1)		(3)
Amortization of net actuarial income (loss)	[3]	0		(2)
Net current period other comprehensive income (loss)		0		2
Accumulated other comprehensive loss at end of period		(1)		(1)		(3)
Defined Benefit Pension and Postretirement Items | Reclassification out of Accumulated Other Comprehensive Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total income tax expense		0		0
Reclassification from AOCI, Current Period, Tax		0		1
Defined Benefit Pension and Postretirement Items | Interest Rate Swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amortization of net actuarial income (loss)		0		0
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive loss at beginning of period		(24)		(27)
Amortization of net actuarial income (loss)		(1)		(2)
Net current period other comprehensive income (loss)		2		3
Accumulated other comprehensive loss at end of period		(22)		(24)		$ (27)
Total | Interest Rate Swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amortization of net actuarial income (loss)		$ (1)		$ (1)
[1]	Included in interest charges.
[2]	Included in interest charges.
[3]	Included in the computation of net periodic pension and postretirement benefit costs. See Note 9 for further information.

Segments and Related Informat_3

Segments and Related Information (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Operating revenue, Regulated Natural Gas										$ 1,355	$ 1,024	$ 1,161
Unregulated Operating Revenue										47	43	43
Regulated and Unregulated Operating Revenue		$ 1,134	$ 1,081	$ 911	$ 1,057	$ 1,134	$ 1,081	$ 911	$ 1,057	4,815	4,183	4,237
Depreciation and amortization										744	655	602
Interest charges and financing costs										234	224	224
Total income tax expense										33	45	80
Net income (loss)		$ 133	$ 218	$ 108	$ 129	$ 133	$ 218	$ 108	$ 129	660	588	578
Intercompany Revenue										5	5	5
Regulated Electric
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues										3,414	3,117	3,034
Depreciation and amortization										566	497	455
Interest charges and financing costs										179	173	173
Total income tax expense										(16)	13	45
Net income (loss)										495	460	465
Regulated Natural Gas
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues										1,355	1,024	1,161
Depreciation and amortization										171	152	141
Interest charges and financing costs										53	50	50
Total income tax expense										45	29	33
Net income (loss)										168	126	119
All Other
Segment Reporting Information [Line Items]
Depreciation and amortization										7	6	6
Interest charges and financing costs										2	1	1
Total income tax expense										4	3	2
Net income (loss)										(3)	2	(6)
Total revenues
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue	[1]									4,816	4,184	4,238
Total revenues | Regulated Electric
Segment Reporting Information [Line Items]
Electric										3,413	3,116	3,033
Total revenues | All Other
Segment Reporting Information [Line Items]
Unregulated Operating Revenue	[1]									47	43	43
Intersegment Eliminations
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue										(1)	(1)	(1)
Intersegment Eliminations | Regulated Electric
Segment Reporting Information [Line Items]
Electric										$ 1	$ 1	$ 1
[1]	Operating revenues include $5 million of other affiliate revenue for the years ended Dec. 31, 2021, 2020 and 2019, respectively. See Note 13 for further information.

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts receivable	$ 13	$ 8
Accounts payable	69	58
NSP-Minnesota
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts receivable	0	0
Accounts payable	16	1
NSP-Wisconsin
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts receivable	0	0
Accounts payable	2	1
SPS
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts receivable	0	0
Accounts payable	7	6
Other subsidiaries of Xcel Energy Inc.
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts receivable	13	8
Accounts payable	44	50
Other Expense
Operating expenses
Costs and Expenses, Related Party	617	571	$ 532
Other Revenue
Operating revenues
Operating Revenue from Related Parties	$ 5	$ 5	$ 5

Summarized Quarterly Financia_3

Summarized Quarterly Financial Data (Unaudited) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Regulated and Unregulated Operating Revenue	$ 1,134	$ 1,081	$ 911	$ 1,057	$ 1,134	$ 1,081	$ 911	$ 1,057	$ 4,815	$ 4,183	$ 4,237
Operating income	176	290	161	196	176	290	161	196	895	823	857
Net income	$ 133	$ 218	$ 108	$ 129	$ 133	$ 218	$ 108	$ 129	$ 660	$ 588	$ 578

Schedule II, Valuation and Qu_2

Schedule II, Valuation and Qualifying Accounts (Details) - Allowance for Bad Debts - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Jan. 1		$ 29	$ 21	$ 21
Charged to costs and expenses		26	24	17
Charged to other accounts	[1]	4	4	6
Deductions from reserves	[2]	(19)	(20)	(23)
Balance at Dec. 31		$ 40	$ 29	$ 21
[1]	Recovery of amounts previously written-off.
[2]	Deductions related primarily to bad debt write-offs