Income Tax - Additional Information (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||||
|---|---|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Income Taxes Disclosure [Line Items] | ||||||
| Income tax expense | $ 100.0 | $ 50.0 | $ 403.0 | $ 292.0 | ||
| Accrued income taxes | 72.0 | 72.0 | $ 154.0 | $ 154.0 | ||
| Increase (decrease) in corporate alternative minimum tax (CAMT) carry forward | 205.0 | |||||
| Estimated liability for uncertain tax positions | 10.0 | 10.0 | ||||
| Unrecognized tax benefits, increase resulting from current period tax positions | 0.9 | |||||
| Unrecognized tax benefits, net | 9.0 | 9.0 | ||||
| Subsidiaries | CECONY | ||||||
| Income Taxes Disclosure [Line Items] | ||||||
| Income tax expense | 98.0 | $ 48.0 | 329.0 | $ 275.0 | ||
| Accrued income taxes | 68.0 | 68.0 | ||||
| Increase (decrease) in corporate alternative minimum tax (CAMT) carry forward | 213.0 | |||||
| Estimated liability for uncertain tax positions | $ 6.0 | 6.0 | ||||
| Unrecognized tax benefits, increase resulting from current period tax positions | $ 0.8 | |||||