Consolidated Balance Sheet (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
CURRENT ASSETS
Cash and temporary cash investments	$ 769	$ 648
Accounts receivable - customers	1,069	1,123
Accrued unbilled revenue	379	474
Other receivables	249	303
Fuel oil, gas in storage, materials and supplies, at average cost	325	356
Prepayments	431	145
Deferred tax assets - current	285	266
Regulatory assets	192	164
Other current assets	205	159
TOTAL CURRENT ASSETS	3,904	3,638
INVESTMENTS	440	455
UTILITY PLANT, AT ORIGINAL COST
General	2,093	1,960
TOTAL	30,449	29,775
Less: Accumulated depreciation	6,153	6,051
Net	24,296	23,724
Construction work in progress	920	1,241
NET UTILITY PLANT	25,216	24,965
NON-UTILITY PLANT
Non-utility property	98	89
Construction work in progress	39	39
NET PLANT	25,353	25,093
OTHER NONCURRENT ASSETS
Goodwill	429	429
Intangible assets, less accumulated amortization of $3 in 2012 and 2011	3	3
Regulatory assets	9,276	9,337
Other deferred charges and noncurrent assets	296	259
TOTAL OTHER NONCURRENT ASSETS	10,004	10,028
TOTAL ASSETS	39,701	39,214
CURRENT LIABILITIES
Long-term debt due within one year	1,030	530
Accounts payable	844	955
Customer deposits	306	303
Accrued taxes	229	188
Accrued interest	212	160
Accrued wages	91	91
Fair value of derivative liabilities	198	169
Regulatory liabilities	286	118
Preferred stock redemption	239
Other current liabilities	405	473
TOTAL CURRENT LIABILITIES	3,840	2,987
NONCURRENT LIABILITIES
Obligations under capital leases	2	2
Provision for injuries and damages	158	181
Pensions and retiree benefits	4,605	4,835
Superfund and other environmental costs	537	489
Asset retirement obligations	147	145
Fair value of derivative liabilities	54	48
Other noncurrent liabilities	131	131
TOTAL NONCURRENT LIABILITIES	5,634	5,831
DEFERRED CREDITS AND REGULATORY LIABILITIES
Deferred income taxes and investment tax credits	7,712	7,563
Regulatory liabilities	846	977
Other deferred credits	83	64
TOTAL DEFERRED CREDITS AND REGULATORY LIABILITIES	8,641	8,604
LONG-TERM DEBT	10,041	10,143
SHAREHOLDERS' EQUITY
Common shareholders' equity (See Statement of Common Shareholders' Equity)	11,545	11,436
Preferred stock of subsidiary		213
TOTAL SHAREHOLDERS' EQUITY	11,545	11,649
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	39,701	39,214
CECONY [Member]
CURRENT ASSETS
Cash and temporary cash investments	475	372
Accounts receivable - customers	934	977
Accrued unbilled revenue	285	366
Other receivables	110	102
Accounts receivable from affiliated companies	36	54
Fuel oil, gas in storage, materials and supplies, at average cost	286	308
Prepayments	372	85
Deferred tax assets - current	170	157
Regulatory assets	159	140
Other current assets	97	100
TOTAL CURRENT ASSETS	2,924	2,661
INVESTMENTS	188	177
UTILITY PLANT, AT ORIGINAL COST
General	1,917	1,785
TOTAL	28,501	27,854
Less: Accumulated depreciation	5,616	5,523
Net	22,885	22,331
Construction work in progress	853	1,165
NET UTILITY PLANT	23,738	23,496
NON-UTILITY PLANT
Non-utility property	6	6
NET PLANT	23,744	23,502
OTHER NONCURRENT ASSETS
Regulatory assets	8,645	8,661
Other deferred charges and noncurrent assets	254	217
TOTAL OTHER NONCURRENT ASSETS	8,899	8,878
TOTAL ASSETS	35,755	35,218
CURRENT LIABILITIES
Long-term debt due within one year	1,024	525
Accounts payable	690	774
Accounts payable to affiliated companies	17	16
Customer deposits	293	290
Accrued taxes	17	32
Accrued taxes to affiliated companies	198	126
Accrued interest	175	133
Accrued wages	82	81
Fair value of derivative liabilities	112	98
Regulatory liabilities	242	79
Preferred stock redemption	239
Other current liabilities	338	396
TOTAL CURRENT LIABILITIES	3,427	2,550
NONCURRENT LIABILITIES
Obligations under capital leases	2	2
Provision for injuries and damages	151	173
Pensions and retiree benefits	4,142	4,337
Superfund and other environmental costs	421	373
Asset retirement obligations	147	145
Fair value of derivative liabilities	31	24
Other noncurrent liabilities	121	120
TOTAL NONCURRENT LIABILITIES	5,015	5,174
DEFERRED CREDITS AND REGULATORY LIABILITIES
Deferred income taxes and investment tax credits	7,059	6,921
Regulatory liabilities	730	861
Other deferred credits	81	61
TOTAL DEFERRED CREDITS AND REGULATORY LIABILITIES	7,870	7,843
LONG-TERM DEBT	9,119	9,220
SHAREHOLDERS' EQUITY
Common shareholders' equity (See Statement of Common Shareholders' Equity)	10,324	10,218
Preferred stock of subsidiary		213
TOTAL SHAREHOLDERS' EQUITY	10,324	10,431
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	35,755	35,218
Electric Transmission [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	21,520	21,105
Electric Transmission [Member] | CECONY [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	20,284	19,886
Gas Transmission [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	4,821	4,727
Gas Transmission [Member] | CECONY [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	4,285	4,200
Steam Plant [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	2,015	1,983
Steam Plant [Member] | CECONY [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	$ 2,015	$ 1,983