Benefit Plans and Other Postretirement Benefits (Details) - USD ($) $ in Millions |
1 Months Ended | 3 Months Ended | 9 Months Ended | ||||||
|---|---|---|---|---|---|---|---|---|---|
Jan. 31, 2024 |
Sep. 30, 2024 |
Sep. 30, 2023 |
Sep. 30, 2024 |
Sep. 30, 2023 |
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| Components of Net Periodic Benefit Cost [Abstract] | |||||||||
| Operating and maintenance expenses | $ 655 | $ 586 | $ 1,922 | $ 1,864 | |||||
| Pension Plan [Member] | |||||||||
| Components of Net Periodic Benefit Cost [Abstract] | |||||||||
| Service cost | 19 | 18 | 57 | 55 | |||||
| Interest Cost | [1] | 37 | 39 | 113 | 119 | ||||
| Expected Return on Plan Assets | [1] | (52) | (52) | (155) | (157) | ||||
| Defined Benefit Plan, Amortization of Prior Service Cost (Credit) | [1] | (1) | (1) | ||||||
| Amortization of Net Loss | [1] | 7 | 6 | 22 | 17 | ||||
| Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement | [2] | 6 | 0 | 62 | 0 | ||||
| Net periodic benefit cost | 17 | 11 | 98 | 33 | |||||
| Effects of regulation | (1) | 11 | (37) | 25 | |||||
| Net benefit cost recognized for financial reporting | 16 | 22 | 61 | 58 | |||||
| Operating and maintenance expenses | 1 | 8 | |||||||
| Pension Plan [Member] | Parent Company | |||||||||
| Components of Net Periodic Benefit Cost [Abstract] | |||||||||
| Contributions to Xcel Energy's pension plans | $ 100 | ||||||||
| Other Postretirement Benefits Plan [Member] | |||||||||
| Components of Net Periodic Benefit Cost [Abstract] | |||||||||
| Service cost | 0 | 0 | 1 | 1 | |||||
| Interest Cost | [1] | 6 | 6 | 16 | 17 | ||||
| Expected Return on Plan Assets | [1] | (4) | (4) | (13) | (13) | ||||
| Defined Benefit Plan, Amortization of Prior Service Cost (Credit) | [1] | 0 | (1) | ||||||
| Amortization of Net Loss | [1] | 0 | 0 | 1 | 1 | ||||
| Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement | [2] | 0 | 0 | 0 | 0 | ||||
| Net periodic benefit cost | 2 | 2 | 5 | 5 | |||||
| Effects of regulation | 0 | 0 | 0 | 0 | |||||
| Net benefit cost recognized for financial reporting | $ 2 | $ 2 | $ 5 | $ 5 | |||||
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