Regulatory Matters - Regulatory Assets and Liabilities (Detail) - USD ($) $ in Millions | Jun. 30, 2015 | Dec. 31, 2014 |
Regulatory assets | | |
Regulatory assets – noncurrent | $ 8,646 | $ 9,156 |
Regulatory assets – current | 75 | 148 |
Total Regulatory Assets | 8,721 | 9,304 |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 1,947 | 1,993 |
Regulatory liabilities – current | 142 | 187 |
Total Regulatory Liabilities | 2,089 | 2,180 |
Unrecognized pension and other postretirement costs | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 4,400 | 4,846 |
Future income tax | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 2,326 | 2,273 |
Deferred storm costs | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 254 | 319 |
Revenue taxes | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 227 | 219 |
Pension and other postretirement benefits deferrals | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 54 | 66 |
Net electric deferrals | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 54 | 63 |
Unamortized loss on reacquired debt | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 54 | 57 |
Deferred derivative losses | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 46 | 25 |
Surcharge for New York State assessment | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 40 | 99 |
O&R property tax reconciliation | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 40 | 36 |
Preferred stock redemption | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 27 | 27 |
O&R transition bond charges | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 24 | 27 |
Recoverable energy costs | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 0 | 19 |
Regulatory assets – current | 2 | 41 |
Other | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 193 | 147 |
Deferred derivative losses | | |
Regulatory assets | | |
Regulatory assets – current | 65 | 97 |
Future income tax | | |
Regulatory assets | | |
Regulatory assets – current | 8 | 10 |
Allowance for cost of removal less salvage | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 620 | 598 |
Property tax reconciliation | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 300 | 295 |
Base rate change deferrals | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 146 | 155 |
Net unbilled revenue deferrals | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 116 | 138 |
Prudence proceeding | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 103 | 105 |
Pension and other postretirement benefit deferrals | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 83 | 46 |
Variable-rate tax-exempt debt – cost rate reconciliation | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 80 | 78 |
Property tax refunds | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 65 | 87 |
New York State income tax rate change | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 64 | 62 |
Carrying charges on repair allowance and bonus depreciation | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 52 | 58 |
World Trade Center settlement proceeds | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 31 | 41 |
Net utility plant reconciliations | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 22 | 21 |
Earnings sharing – electric | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 21 | 19 |
Unrecognized other postretirement costs | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 17 | 0 |
Other | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 227 | 290 |
Refundable energy costs | | |
Regulatory liabilities | | |
Regulatory liabilities – current | 72 | 128 |
Revenue decoupling mechanism | | |
Regulatory liabilities | | |
Regulatory liabilities – current | 42 | 30 |
Future income tax | | |
Regulatory liabilities | | |
Regulatory liabilities – current | 22 | 24 |
Deferred derivative gains | | |
Regulatory liabilities | | |
Regulatory liabilities – current | 6 | 5 |
CECONY | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 8,011 | 8,481 |
Regulatory assets – current | 60 | 132 |
Total Regulatory Assets | 8,071 | 8,613 |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 1,772 | 1,837 |
Regulatory liabilities – current | 107 | 142 |
Total Regulatory Liabilities | 1,879 | 1,979 |
CECONY | Unrecognized pension and other postretirement costs | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 4,191 | 4,609 |
CECONY | Future income tax | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 2,216 | 2,166 |
CECONY | Deferred storm costs | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 167 | 224 |
CECONY | Revenue taxes | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 215 | 208 |
CECONY | Pension and other postretirement benefits deferrals | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 27 | 42 |
CECONY | Net electric deferrals | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 53 | 63 |
CECONY | Unamortized loss on reacquired debt | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 51 | 55 |
CECONY | Deferred derivative losses | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 41 | 23 |
CECONY | Surcharge for New York State assessment | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 38 | 92 |
CECONY | O&R property tax reconciliation | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 0 | 0 |
CECONY | Preferred stock redemption | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 27 | 27 |
CECONY | O&R transition bond charges | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 0 | 0 |
CECONY | Recoverable energy costs | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 0 | 17 |
Regulatory assets – current | 0 | 40 |
CECONY | Other | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 179 | 127 |
CECONY | Deferred derivative losses | | |
Regulatory assets | | |
Regulatory assets – current | 60 | 92 |
CECONY | Future income tax | | |
Regulatory assets | | |
Regulatory assets – current | 0 | 0 |
CECONY | Allowance for cost of removal less salvage | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 518 | 499 |
CECONY | Property tax reconciliation | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 300 | 295 |
CECONY | Base rate change deferrals | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 146 | 155 |
CECONY | Net unbilled revenue deferrals | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 116 | 138 |
CECONY | Prudence proceeding | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 103 | 105 |
CECONY | Pension and other postretirement benefit deferrals | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 59 | 37 |
CECONY | Variable-rate tax-exempt debt – cost rate reconciliation | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 69 | 78 |
CECONY | Property tax refunds | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 65 | 87 |
CECONY | New York State income tax rate change | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 61 | 59 |
CECONY | Carrying charges on repair allowance and bonus depreciation | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 50 | 57 |
CECONY | World Trade Center settlement proceeds | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 31 | 41 |
CECONY | Net utility plant reconciliations | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 23 | 20 |
CECONY | Earnings sharing – electric | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 21 | 18 |
CECONY | Unrecognized other postretirement costs | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 17 | 0 |
CECONY | Other | | |
Regulatory liabilities | | |
Regulatory liabilities – noncurrent | 193 | 248 |
CECONY | Refundable energy costs | | |
Regulatory liabilities | | |
Regulatory liabilities – current | 39 | 84 |
CECONY | Revenue decoupling mechanism | | |
Regulatory liabilities | | |
Regulatory liabilities – current | 41 | 30 |
CECONY | Future income tax | | |
Regulatory liabilities | | |
Regulatory liabilities – current | 21 | 24 |
CECONY | Deferred derivative gains | | |
Regulatory liabilities | | |
Regulatory liabilities – current | 6 | 4 |
Superfund Sites | | |
Regulatory assets | | |
Total Regulatory Assets | 897 | 925 |
Superfund Sites | Environmental remediation costs | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 897 | 925 |
Superfund Sites | CECONY | | |
Regulatory assets | | |
Total Regulatory Assets | 796 | 820 |
Superfund Sites | CECONY | Environmental remediation costs | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 796 | 820 |
Workers’ compensation | | |
Regulatory assets | | |
Total Regulatory Assets | 10 | 8 |
Workers’ compensation | Workers’ compensation | | |
Regulatory assets | | |
Regulatory assets – noncurrent | 10 | 8 |
Workers’ compensation | CECONY | | |
Regulatory assets | | |
Total Regulatory Assets | 10 | 8 |
Workers’ compensation | CECONY | Workers’ compensation | | |
Regulatory assets | | |
Regulatory assets – noncurrent | $ 10 | $ 8 |