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Fair Value of Financial Assets and Liabilities (Tables) | 9 Months Ended
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Sep. 30, 2021
Fair Value Disclosures [Abstract] |
Cost and Fair Value of Nuclear Decommissioning Fund Investments | Non-derivative instruments with recurring fair value measurements in the nuclear decommissioning fund:
|  | Sept. 30, 2021
|  |  |  | Fair Value
(Millions of Dollars) |  | Cost |  | Level 1 |  | Level 2 |  | Level 3 |  | NAV |  | Total
Nuclear decommissioning fund (a) |  |  |  |  |  |  |  |  |  |  |  |
Cash equivalents |  | $ | 38 |  |  | $ | 38 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 38 |
Commingled funds |  | 821 |  |  | — |  |  | — |  |  | — |  |  | 1,208 |  |  | 1,208 |
Debt securities |  | 620 |  |  | — |  |  | 643 |  |  | 15 |  |  | — |  |  | 658 |
Equity securities |  | 407 |  |  | 1,178 |  |  | 2 |  |  | — |  |  | — |  |  | 1,180 |
Total |  | $ | 1,886 |  |  | $ | 1,216 |  |  | $ | 645 |  |  | $ | 15 |  |  | $ | 1,208 |  |  | $ | 3,084 |
(a) Reported in nuclear decommissioning fund and other investments on the consolidated balance sheets, which also includes $204 million of equity method investments and $158 million of rabbi trust assets and miscellaneous investments.
|  | Dec. 31, 2020
|  |  |  | Fair Value
(Millions of Dollars) |  | Cost |  | Level 1 |  | Level 2 |  | Level 3 |  | NAV |  | Total
Nuclear decommissioning fund (a) |  |  |  |  |  |  |  |  |  |  |  |
Cash equivalents |  | $ | 40 |  |  | $ | 40 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 40 |
Commingled funds |  | 787 |  |  | — |  |  | — |  |  | — |  |  | 1,041 |  |  | 1,041 |
Debt securities |  | 528 |  |  | — |  |  | 572 |  |  | 13 |  |  | — |  |  | 585 |
Equity securities |  | 446 |  |  | 1,109 |  |  | 2 |  |  | — |  |  | — |  |  | 1,111 |
Total |  | $ | 1,801 |  |  | $ | 1,149 |  |  | $ | 574 |  |  | $ | 13 |  |  | $ | 1,041 |  |  | $ | 2,777 |
(a)Reported in nuclear decommissioning fund and other investments on the consolidated balance sheets, which also includes $165 million of equity method investments and $154 million of rabbi trust assets and other miscellaneous investments.
Final Contractual Maturity Dates of Debt Securities in the Nuclear Decommissioning Fund by Asset Class | Contractual maturity dates of debt securities in the nuclear decommissioning fund as of Sept. 30, 2021:
|  | Final Contractual Maturity
(Millions of Dollars) |  | Due in 1 year or Less |  | Due in 1 to 5 Years |  | Due in 5 to 10 Years |  | Due after 10 years |  | Total
Debt securities |  | $ | 2 |  |  | $ | 153 |  |  | $ | 204 |  |  | $ | 299 |  |  | $ | 658 |
Rabbi Trust Securities Amortized Cost and Fair Value Measured on Recurrring Basis [Table Text Block] | Cost and fair value of assets held in rabbi trusts:
|  | Sept. 30, 2021
|  |  |  | Fair Value
(Millions of Dollars) |  | Cost |  | Level 1 |  | Level 2 |  | Level 3 |  | Total
Rabbi Trusts (a) |  |  |  |  |  |  |  |  |  |
Cash equivalents |  | $ | 17 |  |  | $ | 17 |  |  | $ | — |  |  | $ | — |  |  | $ | 17 |
Mutual funds |  | 71 |  |  | 84 |  |  | — |  |  | — |  |  | 84 |
Total |  | $ | 88 |  |  | $ | 101 |  |  | $ | — |  |  | $ | — |  |  | $ | 101 |
|  | Dec. 31, 2020
|  |  |  | Fair Value
(Millions of Dollars) |  | Cost |  | Level 1 |  | Level 2 |  | Level 3 |  | Total
Rabbi Trusts (a) |  |  |  |  |  |  |  |  |  |
Cash equivalents |  | $ | 32 |  |  | $ | 32 |  |  | $ | — |  |  | $ | — |  |  | $ | 32 |
Mutual funds |  | 60 |  |  | 70 |  |  | — |  |  | — |  |  | 70 |
Total |  | $ | 92 |  |  | $ | 102 |  |  | $ | — |  |  | $ | — |  |  | $ | 102 |
(a) Reported in nuclear decommissioning fund and other investments on the consolidated balance sheets.
Gross Notional Amounts of Commodity Forwards, Options, and FTRs | Gross notional amounts of commodity forwards, options and FTRs:
(Amounts in Millions) (a)(b) |  | Sept. 30, 2021 |  | Dec. 31, 2020
Megawatt hours of electricity |  | 101 |  |  | 87 |
Million British thermal units of natural gas |  | 184 |  |  | 175 |
(a)Not reflective of net positions in the underlying commodities. (b)Notional amounts for options included on a gross basis but weighted for the probability of exercise.
Impact of Derivative Activity on Accumulated Other Comprehensive Loss, Regulatory Assets and Liabilities, and Income | Impact of Derivative Activity —
|  | Pre-Tax Fair Value Gains (Losses) Recognized During the Period in:
(Millions of Dollars) |  | Accumulated Other Comprehensive Loss |  | Regulatory (Assets) and Liabilities
Three Months Ended Sept. 30, 2021 |  |  |  |
Derivatives designated as cash flow hedges: |  |
Interest rate |  | $ | 4 |  |  | $ | — |
Total |  | $ | 4 |  |  | $ | — |
Other derivative instruments: |  |  |  |
Electric commodity |  | $ | — |  |  | $ | 5 |
Natural gas commodity |  | — |  |  | 57 |
Total |  | $ | — |  |  | $ | 62 |
Nine Months Ended Sept. 30, 2021 |  |  |  |
Derivatives designated as cash flow hedges: |  |
Interest rate |  | $ | 5 |  |  | $ | — |
Total |  | $ | 5 |  |  | $ | — |
Other derivative instruments: |  |  |  |
Electric commodity |  | $ | — |  |  | $ | 18 |
Natural gas commodity |  | — |  |  | 57 |
Total |  | $ | — |  |  | $ | 75 |
Three Months Ended Sept. 30, 2020 |  |  |  |
Other derivative instruments: |  |  |  |
Electric commodity |  | $ | — |  |  | $ | (3) |
Natural gas commodity |  | — |  |  | 2 |
Total |  | $ | — |  |  | $ | (1) |
Nine Months Ended Sept. 30, 2020 |  |  |  |
Derivatives designated as cash flow hedges: |  |
Interest rate |  | $ | (13) |  |  | $ | — |
Total |  | $ | (13) |  |  | $ | — |
Other derivative instruments: |  |  |  |
Electric commodity |  | $ | — |  |  | $ | (3) |
Natural gas commodity |  | — |  |  | (1) |
Total |  | $ | — |  |  | $ | (4) |
|  | Pre-Tax (Gains) Losses Reclassified into Income During the Period from: |  | Pre-Tax Gains (Losses) Recognized During the Period in Income |
(Millions of Dollars) |  | Accumulated Other Comprehensive Loss |  | Regulatory Assets and (Liabilities) |  |
Three Months Ended Sept. 30, 2021 |  |  |  |  |
Derivatives designated as cash flow hedges: |  |  |  |  |
Interest rate |  | $ | 2 |  | (a) | $ | — |  |  | $ | — |  |
Total |  | $ | 2 |  |  | $ | — |  |  | $ | — |  |
Other derivative instruments: |  |  |  |  |  |  |
Commodity trading |  | $ | — |  |  | $ | — |  |  | $ | 1 |  | (b)
Electric commodity |  | — |  |  | 3 |  | (c) | — |  |
Total |  | $ | — |  |  | $ | 3 |  |  | $ | 1 |  |
Nine Months Ended Sept. 30, 2021 |  |  |  |  |
Derivatives designated as cash flow hedges: |  |  |  |  |
Interest rate |  | $ | 7 |  | (a) | $ | — |  |  | $ | — |  |
Total |  | $ | 7 |  |  | $ | — |  |  | $ | — |  |
Other derivative instruments: |  |  |  |  |  |  |
Commodity trading |  | $ | — |  |  | $ | — |  |  | $ | 49 |  | (b)
Electric commodity |  | — |  |  | (26) |  | (c) | — |  |
Natural gas commodity |  | — |  |  | 8 |  | (d) | (10) |  | (d)
Total |  | $ | — |  |  | $ | (18) |  |  | $ | 39 |  |
Three Months Ended Sept. 30, 2020 |  |  |  |  |
Derivatives designated as cash flow hedges: |  |  |  |  |
Interest rate |  | $ | 1 |  | (a) | $ | — |  |  | $ | — |  |
Total |  | $ | 1 |  |  | $ | — |  |  | $ | — |  |
Other derivative instruments: |  |  |  |  |  |  |
Commodity trading |  | $ | — |  |  | $ | — |  |  | $ | 2 |  | (b)
Electric commodity |  | — |  |  | (3) |  | (c) | — |  |
Total |  | $ | — |  |  | $ | (3) |  |  | $ | 2 |  |
Nine Months Ended Sept. 30, 2020 |  |  |  |  |
Derivatives designated as cash flow hedges: |  |  |  |  |
Interest rate |  | $ | 5 |  | (a) | $ | — |  |  | $ | — |  |
Total |  | $ | 5 |  |  | $ | — |  |  | $ | — |  |
Other derivative instruments: |  |  |  |  |  |  |
Commodity trading |  | $ | — |  |  | $ | — |  |  | $ | (1) |  | (b)
Electric commodity |  | — |  |  | (6) |  | (c) | — |  |
Natural gas commodity |  | — |  |  | 5 |  | (d) | (6) |  | (d)
Total |  | $ | — |  |  | $ | (1) |  |  | $ | (7) |  |
(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)Recorded to electric fuel and purchased power. These derivative settlement gains and losses are shared with electric customers through fuel and purchased energy cost-recovery mechanisms, and reclassified out of income as regulatory assets or liabilities, as appropriate. (d)Amounts for both the three and nine months ended Sept. 30, 2021 and 2020 included no settlement gains or losses on derivatives entered to mitigate natural gas price risk for electric generation recorded to electric fuel and purchased power, subject to cost-recovery mechanisms and reclassified to a regulatory asset, as appropriate. Remaining settlement losses for both the three and nine months ended Sept. 30, 2021 and 2020 relate to natural gas operations and were recorded to cost of natural gas sold and transported. These gains and losses are subject to cost-recovery mechanisms and reclassified out of income to a regulatory asset or liability, as appropriate.
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] | Recurring Fair Value Measurements — Derivative assets and liabilities measured at fair value on a recurring basis:
|  | Sept. 30, 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 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivatives designated as cash flow hedges: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest rate |  | $ | — |  |  | $ | 4 |  |  | $ | — |  |  | $ | 4 |  |  | $ | — |  |  | $ | 4 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |
Other derivative instruments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commodity trading |  | $ | 50 |  |  | $ | 240 |  |  | $ | 23 |  |  | $ | 313 |  |  | $ | (253) |  |  | $ | 60 |  |  | $ | 2 |  |  | $ | 67 |  |  | $ | 1 |  |  | $ | 70 |  |  | $ | (52) |  |  | $ | 18 |
Electric commodity |  | — |  |  | — |  |  | 83 |  |  | 83 |  |  | (1) |  |  | 82 |  |  | — |  |  | — |  |  | 20 |  |  | 20 |  |  | (1) |  |  | 19 |
Natural gas commodity |  | — |  |  | 79 |  |  | — |  |  | 79 |  |  | — |  |  | 79 |  |  | — |  |  | 9 |  |  | — |  |  | 9 |  |  | — |  |  | 9 |
Total current derivative assets |  | $ | 50 |  |  | $ | 323 |  |  | $ | 106 |  |  | $ | 479 |  |  | $ | (254) |  |  | 225 |  |  | $ | 2 |  |  | $ | 76 |  |  | $ | 21 |  |  | $ | 99 |  |  | $ | (53) |  |  | 46 |
PPAs (b) |  |  |  |  |  |  |  |  |  |  |  | 3 |  |  |  |  |  |  |  |  |  |  |  |  | 3 |
Current derivative instruments |  |  |  |  |  |  |  |  |  |  |  | $ | 228 |  |  |  |  |  |  |  |  |  |  |  |  | $ | 49 |
Noncurrent derivative assets |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other derivative instruments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commodity trading |  | $ | 23 |  |  | $ | 72 |  |  | $ | 99 |  |  | $ | 194 |  |  | $ | (129) |  |  | $ | 65 |  |  | $ | 8 |  |  | $ | 66 |  |  | $ | 8 |  |  | $ | 82 |  |  | $ | (62) |  |  | $ | 20 |
Total noncurrent derivative assets |  | $ | 23 |  |  | $ | 72 |  |  | $ | 99 |  |  | $ | 194 |  |  | $ | (129) |  |  | 65 |  |  | $ | 8 |  |  | $ | 66 |  |  | $ | 8 |  |  | $ | 82 |  |  | $ | (62) |  |  | 20 |
PPAs (b) |  |  |  |  |  |  |  |  |  |  |  | 7 |  |  |  |  |  |  |  |  |  |  |  |  | 10 |
Noncurrent derivative instruments |  |  |  |  |  |  |  |  |  |  |  | $ | 72 |  |  |  |  |  |  |  |  |  |  |  |  | $ | 30 |
|  | Sept. 30, 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 liabilities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other derivative instruments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commodity trading |  | $ | 48 |  |  | $ | 239 |  |  | $ | 25 |  |  | $ | 312 |  |  | $ | (253) |  |  | $ | 59 |  |  | $ | 4 |  |  | $ | 64 |  |  | $ | 17 |  |  | $ | 85 |  |  | $ | (58) |  |  | $ | 27 |
Electric commodity |  | — |  |  | — |  |  | 1 |  |  | 1 |  |  | (1) |  |  | — |  |  | — |  |  | — |  |  | 1 |  |  | 1 |  |  | (1) |  |  | — |
Natural gas commodity |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 9 |  |  | — |  |  | 9 |  |  | — |  |  | 9 |
Total current derivative liabilities |  | $ | 48 |  |  | $ | 239 |  |  | $ | 26 |  |  | $ | 313 |  |  | $ | (254) |  |  | 59 |  |  | $ | 4 |  |  | $ | 73 |  |  | $ | 18 |  |  | $ | 95 |  |  | $ | (59) |  |  | 36 |
PPAs (b) |  |  |  |  |  |  |  |  |  |  |  | 17 |  |  |  |  |  |  |  |  |  |  |  |  | 17 |
Current derivative instruments |  |  |  |  |  |  |  |  |  |  |  | $ | 76 |  |  |  |  |  |  |  |  |  |  |  |  | $ | 53 |
Noncurrent derivative liabilities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other derivative instruments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commodity trading |  | $ | 22 |  |  | $ | 69 |  |  | $ | 120 |  |  | $ | 211 |  |  | $ | (156) |  |  | $ | 55 |  |  | $ | 3 |  |  | $ | 58 |  |  | $ | 60 |  |  | $ | 121 |  |  | $ | (47) |  |  | $ | 74 |
Total noncurrent derivative liabilities |  | $ | 22 |  |  | $ | 69 |  |  | $ | 120 |  |  | $ | 211 |  |  | $ | (156) |  |  | 55 |  |  | $ | 3 |  |  | $ | 58 |  |  | $ | 60 |  |  | $ | 121 |  |  | $ | (47) |  |  | 74 |
PPAs (b) |  |  |  |  |  |  |  |  |  |  |  | 44 |  |  |  |  |  |  |  |  |  |  |  |  | 57 |
Noncurrent derivative instruments |  |  |  |  |  |  |  |  |  |  |  | $ | 99 |  |  |  |  |  |  |  |  |  |  |  |  | $ | 131 |
(a)Xcel Energy nets derivative instruments and related collateral on its consolidated balance sheets when supported by a legally enforceable master netting agreement, and all derivative instruments and related collateral amounts were subject to master netting agreements at Sept. 30, 2021 and Dec. 31, 2020. At both Sept. 30, 2021 and Dec. 31, 2020, derivative assets and liabilities include $15 million of obligations to return cash collateral. At Sept. 30, 2021 and Dec. 31, 2020, derivative assets and liabilities include rights to reclaim cash collateral of $42 million and $6 million, respectively. Counterparty netting amounts presented exclude settlement receivables and payables and non-derivative amounts that may be subject to the same master netting agreements. (b)During 2006, Xcel Energy qualified these contracts under the normal purchase exception. Based on this qualification, contracts are no longer adjusted to fair value and the previous carrying value of these contracts is being amortized over the remaining contract lives along with the offsetting regulatory assets and liabilities.
Change in Level 3 Commodity Derivative | Changes in Level 3 commodity derivatives:
|  | Three Months Ended Sept. 30
(Millions of Dollars) |  | 2021 |  | 2020
Balance at July 1 |  | $ | 71 |  |  | $ | 34 |
Purchases |  | 2 |  |  | — |
Settlements |  | (53) |  |  | (17) |
Net transactions recorded during the period: |  |  |  |
Gains (losses) recognized in earnings (a) |  | 12 |  |  | (25) |
Net gains recognized as regulatory assets and liabilities |  | 27 |  |  | 2 |
Balance at Sept. 30 |  | $ | 59 |  |  | $ | (6) |
|  | Nine Months Ended Sept. 30
(Millions of Dollars) |  | 2021 |  | 2020
Balance at Jan. 1 |  | $ | (49) |  |  | $ | 4 |
Purchases |  | 65 |  |  | 49 |
Settlements |  | (101) |  |  | (59) |
Net transactions recorded during the period: |  |  |  |
Gains (losses) recognized in earnings (a) |  | 59 |  |  | (11) |
Net gains recognized as regulatory assets and liabilities |  | 85 |  |  | 11 |
Balance at Sept. 30 |  | $ | 59 |  |  | $ | (6) |
(a)Presented amounts relate to instruments held at the end of the period. The consolidated income statement also includes gains and losses on Level 1 and 2 instruments, and Level 3 instruments settled during the period.
Carrying Amount and Fair Value of Long-term Debt | Other financial instruments for which the carrying amount did not equal fair value:
|  | Sept. 30, 2021 |  | Dec. 31, 2020
(Millions of Dollars) |  | Carrying Amount |  | Fair Value |  | Carrying Amount |  | Fair Value
Long-term debt, including current portion |  | $ | 21,600 |  |  | $ | 24,657 |  |  | $ | 20,066 |  |  | $ | 24,412 |

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- Definition Tabular disclosure of the notional amounts of outstanding derivative positions. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 + Details
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- Definition Tabular disclosure of the amortized cost of available-for-sale securities. Also includes the fair value of these assets measured on a recurring basis in their entirety and the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets or liabilities (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). + References No definition available. + Details
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- Definition Tabular disclosure of the amortized cost of assets held in rabbi trust. Also includes the fair value of these assets measured on a recurring basis in their entirety and the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets or liabilities (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). + References No definition available. + Details
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