Consolidated Balance Sheet (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
NON-UTILITY PLANT
Non-utility property, less accumulated depreciation of $25 and $24 in 2012 and 2011, respectively	$ 99	$ 89
Construction work in progress	400	39
NET PLANT	26,324	25,093
OTHER NONCURRENT ASSETS
Goodwill	429	429
Intangible assets, less accumulated amortization of $3 in 2012 and 2011	3	3
Regulatory assets	8,897	9,337
Other deferred charges and noncurrent assets	278	259
TOTAL OTHER NONCURRENT ASSETS	9,607	10,028
TOTAL ASSETS	39,633	39,214
CURRENT ASSETS
Cash and temporary cash investments	69	648
Accounts receivable - customers, less allowance for uncollectible accounts of $79 in 2012 and 2011	1,319	1,123
Other receivables	216	303
Accrued unbilled revenue	451	474
Fuel oil, gas in storage, materials and supplies, at average cost	355	356
Prepayments	433	145
Regulatory assets	77	164
Deferred tax assets - current	113	266
Other current assets	207	159
TOTAL CURRENT ASSETS	3,240	3,638
INVESTMENTS	462	455
UTILITY PLANT, AT ORIGINAL COST
General	2,253	1,944
TOTAL	31,315	29,775
Less: Accumulated depreciation	6,388	6,051
Net	24,927	23,724
Construction work in progress	898	1,241
NET UTILITY PLANT	25,825	24,965
CURRENT LIABILITIES
Long-term debt due within one year	930	530
Notes payable	340
Accounts payable	968	955
Customer deposits	308	303
Accrued taxes	108	188
Accrued interest	206	160
Accrued wages	88	91
Fair value of derivative liabilities	56	169
Regulatory liabilities	231	118
Other current liabilities	489	473
TOTAL CURRENT LIABILITIES	3,724	2,987
NONCURRENT LIABILITIES
Obligations under capital leases	2	2
Provision for injuries and damages	145	181
Pensions and retiree benefits	4,039	4,835
Superfund and other environmental costs	537	489
Asset retirement obligations	149	145
Fair value of derivative liabilities	34	48
Other noncurrent liabilities	124	131
TOTAL NONCURRENT LIABILITIES	5,030	5,831
DEFERRED CREDITS AND REGULATORY LIABILITIES
Deferred income taxes and investment tax credits	8,026	7,563
Regulatory liabilities	1,102	977
Other deferred credits	70	64
TOTAL DEFERRED CREDITS AND REGULATORY LIABILITIES	9,198	8,604
LONG-TERM DEBT	9,839	10,143
SHAREHOLDER'S EQUITY
Common shareholder's equity (See Statement of Common Shareholder's Equity)	11,842	11,436
Preferred stock of subsidiary		213
TOTAL SHAREHOLDER'S EQUITY	11,842	11,649
TOTAL LIABILITIES AND SHAREHOLDER'S EQUITY	39,633	39,214
CECONY [Member]
NON-UTILITY PLANT
Non-utility property, less accumulated depreciation of $25 and $24 in 2012 and 2011, respectively	4	6
NET PLANT	24,311	23,502
OTHER NONCURRENT ASSETS
Regulatory assets	8,285	8,661
Other deferred charges and noncurrent assets	241	217
TOTAL OTHER NONCURRENT ASSETS	8,526	8,878
TOTAL ASSETS	35,699	35,218
CURRENT ASSETS
Cash and temporary cash investments	26	372
Accounts receivable - customers, less allowance for uncollectible accounts of $79 in 2012 and 2011	1,174	977
Other receivables	103	102
Accrued unbilled revenue	347	366
Accounts receivable from affiliated companies	82	54
Fuel oil, gas in storage, materials and supplies, at average cost	296	308
Prepayments	393	85
Regulatory assets	62	140
Deferred tax assets - current	62	157
Other current assets	114	100
TOTAL CURRENT ASSETS	2,659	2,661
INVESTMENTS	203	177
UTILITY PLANT, AT ORIGINAL COST
General	2,081	1,785
TOTAL	29,291	27,854
Less: Accumulated depreciation	5,834	5,523
Net	23,457	22,331
Construction work in progress	850	1,165
NET UTILITY PLANT	24,307	23,496
CURRENT LIABILITIES
Long-term debt due within one year	925	525
Notes payable	332
Accounts payable	772	774
Accounts payable to affiliated companies	22	16
Customer deposits	295	290
Accrued taxes	33	32
Accrued taxes to affiliated companies	165	126
Accrued interest	179	133
Accrued wages	83	81
Fair value of derivative liabilities	30	98
Regulatory liabilities	199	79
Other current liabilities	400	396
TOTAL CURRENT LIABILITIES	3,435	2,550
NONCURRENT LIABILITIES
Obligations under capital leases	2	2
Provision for injuries and damages	138	173
Pensions and retiree benefits	3,627	4,337
Superfund and other environmental costs	423	373
Asset retirement obligations	148	145
Fair value of derivative liabilities	12	24
Other noncurrent liabilities	116	120
TOTAL NONCURRENT LIABILITIES	4,466	5,174
DEFERRED CREDITS AND REGULATORY LIABILITIES
Deferred income taxes and investment tax credits	7,301	6,921
Regulatory liabilities	978	861
Other deferred credits	67	61
TOTAL DEFERRED CREDITS AND REGULATORY LIABILITIES	8,346	7,843
LONG-TERM DEBT	8,920	9,220
SHAREHOLDER'S EQUITY
Common shareholder's equity (See Statement of Common Shareholder's Equity)	10,532	10,218
Preferred stock of subsidiary		213
TOTAL SHAREHOLDER'S EQUITY	10,532	10,431
TOTAL LIABILITIES AND SHAREHOLDER'S EQUITY	35,699	35,218
Electric Transmission [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	22,019	21,114
Electric Transmission [Member] | CECONY [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	20,728	19,886
Gas Transmission [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	5,009	4,734
Gas Transmission [Member] | CECONY [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	4,448	4,200
Steam Plant [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	2,034	1,983
Steam Plant [Member] | CECONY [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	$ 2,034	$ 1,983