Consolidated Balance Sheet (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
CURRENT ASSETS
Cash and temporary cash investments	$ 648	$ 338
Accounts receivable - customers, less allowance for uncollectible accounts	1,123	1,173
Accrued unbilled revenue	474	633
Other receivables, less allowance for uncollectible accounts	303	293
Fuel oil, gas in storage, materials and supplies, at average cost	356	348
Prepayments	145	341
Deferred tax assets - Current	266	162
Regulatory assets	164	203
Other current assets	159	178
TOTAL CURRENT ASSETS	3,638	3,669
INVESTMENTS	455	403
UTILITY PLANT AT ORIGINAL COST
General	1,960	1,911
TOTAL	29,775	28,144
Less: Accumulated depreciation	6,051	5,808
Net	23,724	22,336
Construction work in progress	1,241	1,458
NET UTILITY PLANT	24,965	23,794
NON-UTILITY PLANT
Non-utility property, less accumulated depreciation	89	46
Construction work in progress	39	23
NET PLANT	25,093	23,863
OTHER NONCURRENT ASSETS
Goodwill	429	429
Intangible assets, less accumulated amortization of $3 in 2011 and 2010	3	3
Regulatory assets	9,337	7,683
Other deferred charges and noncurrent assets	259	298
TOTAL OTHER NONCURRENT ASSETS	10,028	8,413
TOTAL ASSETS	39,214	36,348
CURRENT LIABILITIES
Long-term debt due within one year	530	5
Accounts payable	961	1,151
Customer deposits	303	289
Accrued taxes	188	90
Accrued interest	160	155
Accrued wages	90	102
Fair value of derivative liabilities	169	125
Regulatory liabilities	118	159
Other current liabilities	468	454
TOTAL CURRENT LIABILITIES	2,987	2,530
NONCURRENT LIABILITIES
Obligations under capital leases	2	7
Provision for injuries and damages	181	165
Pensions and retiree benefits	4,835	3,287
Superfund and other environmental costs	489	512
Asset retirement obligations	145	109
Fair value of derivative liabilities	48	77
Other noncurrent liabilities	131	113
TOTAL NONCURRENT LIABILITIES	5,831	4,270
DEFERRED CREDITS AND REGULATORY LIABILITIES
Deferred income taxes and investment tax credits	7,563	6,769
Regulatory liabilities	977	788
Other deferred credits	64	46
TOTAL DEFERRED CREDITS AND REGULATORY LIABILITIES	8,604	7,603
LONG-TERM DEBT (See Statement of Capitalization)	10,143	10,671
SHAREHOLDER'S EQUITY
Common shareholders' equity (See Statement of Common Shareholders' Equity)	11,436	11,061
Preferred stock of subsidiary (See Statement of Capitalization)	213	213
TOTAL SHAREHOLDER'S EQUITY	11,649	11,274
TOTAL LIABILITIES AND SHAREHOLDER'S EQUITY	39,214	36,348
CECONY [Member]
CURRENT ASSETS
Cash and temporary cash investments	372	78
Accounts receivable - customers, less allowance for uncollectible accounts	977	1,025
Accrued unbilled revenue	366	473
Other receivables, less allowance for uncollectible accounts	102	73
Accounts receivable from affiliated companies	54	273
Fuel oil, gas in storage, materials and supplies, at average cost	308	306
Prepayments	85	82
Deferred tax assets - Current	157	131
Regulatory assets	140	151
Other current assets	100	104
TOTAL CURRENT ASSETS	2,661	2,696
INVESTMENTS	177	167
UTILITY PLANT AT ORIGINAL COST
General	1,785	1,746
TOTAL	27,854	26,363
Less: Accumulated depreciation	5,523	5,314
Net	22,331	21,049
Construction work in progress	1,165	1,345
NET UTILITY PLANT	23,496	22,394
NON-UTILITY PLANT
Non-utility property, less accumulated depreciation	6	7
NET PLANT	23,502	22,401
OTHER NONCURRENT ASSETS
Regulatory assets	8,661	7,097
Other deferred charges and noncurrent assets	217	244
TOTAL OTHER NONCURRENT ASSETS	8,878	7,341
TOTAL ASSETS	35,218	32,605
CURRENT LIABILITIES
Long-term debt due within one year	525
Accounts payable	774	924
Accounts payable to affiliated companies	16	13
Customer deposits	290	276
Accrued taxes	32	34
Accrued taxes to affiliated companies	126	29
Accrued interest	133	130
Accrued wages	81	93
Fair value of derivative liabilities	98	71
Regulatory liabilities	79	131
Other current liabilities	396	400
TOTAL CURRENT LIABILITIES	2,550	2,101
NONCURRENT LIABILITIES
Obligations under capital leases	2	7
Provision for injuries and damages	173	159
Pensions and retiree benefits	4,337	2,900
Superfund and other environmental costs	373	392
Asset retirement obligations	145	109
Fair value of derivative liabilities	24	29
Other noncurrent liabilities	120	102
TOTAL NONCURRENT LIABILITIES	5,174	3,698
DEFERRED CREDITS AND REGULATORY LIABILITIES
Deferred income taxes and investment tax credits	6,921	6,202
Regulatory liabilities	861	683
Other deferred credits	61	42
TOTAL DEFERRED CREDITS AND REGULATORY LIABILITIES	7,843	6,927
LONG-TERM DEBT (See Statement of Capitalization)	9,220	9,743
SHAREHOLDER'S EQUITY
Common shareholders' equity (See Statement of Common Shareholders' Equity)	10,218	9,923
Preferred stock of subsidiary (See Statement of Capitalization)	213	213
TOTAL SHAREHOLDER'S EQUITY	10,431	10,136
TOTAL LIABILITIES AND SHAREHOLDER'S EQUITY	35,218	32,605
Electric Transmission [Member]
UTILITY PLANT AT ORIGINAL COST
Utility plant, at original cost	21,105	19,851
Electric Transmission [Member] | CECONY [Member]
UTILITY PLANT AT ORIGINAL COST
Utility plant, at original cost	19,886	18,735
Gas Transmission [Member]
UTILITY PLANT AT ORIGINAL COST
Utility plant, at original cost	4,727	4,344
Gas Transmission [Member] | CECONY [Member]
UTILITY PLANT AT ORIGINAL COST
Utility plant, at original cost	4,200	3,844
Steam Plant [Member]
UTILITY PLANT AT ORIGINAL COST
Utility plant, at original cost	1,983	2,038
Steam Plant [Member] | CECONY [Member]
UTILITY PLANT AT ORIGINAL COST
Utility plant, at original cost	$ 1,983	$ 2,038