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Electric Operating Revenues - Narrative (Details) | Mar. 31, 2019 USD ($) utility | Dec. 31, 2018 USD ($)
--- | --- | ---
Disaggregation of Revenue [Line Items] |  |
Number of regulated utilities | utility | 2 |
Contract assets | $ 0 | $ 0
Customer contracts | PNM |  |
Disaggregation of Revenue [Line Items] |  |
Accounts receivable | $ 65,200,000 | $ 61,700,000

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