CONSOLIDATED BALANCE SHEET (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
CURRENT ASSETS
Cash and temporary cash investments	$ 132	$ 394
Special deposits	508	70
Accounts receivable - customers, less allowance for uncollectible accounts	1,357	1,222
Other receivables, less allowance for uncollectible accounts	213	228
Accrued unbilled revenue	399	516
Fuel oil, gas in storage, materials and supplies, at average cost	270	330
Prepayments	422	159
Regulatory assets	32	74
Deferred tax assets - current	440	296
Other current assets	161	162
TOTAL CURRENT ASSETS	3,934	3,451
INVESTMENTS	351	467
NON-UTILITY PLANT
Non-utility property, less accumulated depreciation	527	555
Construction work in progress	160	83
NET PLANT	27,283	26,939
UTILITY PLANT, AT ORIGINAL COST
General	2,291	2,302
TOTAL	32,103	31,847
Less: Accumulated depreciation	6,716	6,573
Net	25,387	25,274
Construction work in progress	1,209	1,027
NET UTILITY PLANT	26,596	26,301
OTHER NONCURRENT ASSETS
Goodwill	429	429
Intangible assets, less accumulated amortization of $4 in 2013 and 2012	2	2
Regulatory assets	9,484	9,705
Other deferred charges and noncurrent assets	253	216
TOTAL OTHER NONCURRENT ASSETS	10,168	10,352
TOTAL ASSETS	41,736	41,209
CURRENT LIABILITIES
Long-term debt due within one year	405	706
Notes payable	1,021	539
Accounts payable	1,065	1,215
Customer deposits	307	304
Accrued taxes	144	162
Accrued interest	327	153
Accrued wages	93	94
Fair value of derivative liabilities	15	47
Uncertain income tax liabilities	251	44
Regulatory liabilities	132	183
Other current liabilities	483	498
TOTAL CURRENT LIABILITIES	4,243	3,945
NONCURRENT LIABILITIES
Obligations under capital leases	2	2
Provision for injuries and damages	152	149
Pensions and retiree benefits	4,438	4,678
Superfund and other environmental costs	536	545
Asset retirement obligations	160	159
Fair value of derivative liabilities	26	31
Other noncurrent liabilities	125	125
TOTAL NONCURRENT LIABILITIES	5,439	5,689
DEFERRED CREDITS AND REGULATORY LIABILITIES
Deferred income taxes and investment tax credits	8,316	8,372
Regulatory liabilities	1,234	1,202
Other deferred credits	61	70
TOTAL DEFERRED CREDITS AND REGULATORY LIABILITIES	9,611	9,644
LONG-TERM DEBT	10,554	10,062
COMMON SHAREHOLDER'S EQUITY (See Statement of Common Shareholder's Equity)	11,889	11,869
TOTAL LIABILITIES AND SHAREHOLDER'S EQUITY	41,736	41,209
Electric Transmission [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	22,547	22,376
Gas Transmission [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	5,197	5,120
Steam Plant [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	2,068	2,049
CECONY [Member]
CURRENT ASSETS
Cash and temporary cash investments	39	353
Special deposits	57	65
Accounts receivable - customers, less allowance for uncollectible accounts	1,210	1,108
Other receivables, less allowance for uncollectible accounts	86	106
Accrued unbilled revenue	304	406
Accounts receivable from affiliated companies	143	61
Fuel oil, gas in storage, materials and supplies, at average cost	236	285
Prepayments	391	81
Regulatory assets	28	60
Deferred tax assets - current	176	193
Other current assets	35	69
TOTAL CURRENT ASSETS	2,705	2,787
INVESTMENTS	215	207
NON-UTILITY PLANT
Non-utility property, less accumulated depreciation	5	6
NET PLANT	25,032	24,745
UTILITY PLANT, AT ORIGINAL COST
General	2,115	2,126
TOTAL	30,042	29,801
Less: Accumulated depreciation	6,142	6,009
Net	23,900	23,792
Construction work in progress	1,127	947
NET UTILITY PLANT	25,027	24,739
OTHER NONCURRENT ASSETS
Regulatory assets	8,774	8,972
Other deferred charges and noncurrent assets	188	174
TOTAL OTHER NONCURRENT ASSETS	8,962	9,146
TOTAL ASSETS	36,914	36,885
CURRENT LIABILITIES
Long-term debt due within one year	400	700
Notes payable	313	421
Accounts payable	890	989
Accounts payable to affiliated companies	16	22
Customer deposits	295	292
Accrued taxes	21	37
Accrued taxes to affiliated companies	152	215
Accrued interest	179	133
Accrued wages	84	84
Fair value of derivative liabilities	9	28
Uncertain income tax liabilities	7	36
Regulatory liabilities	98	145
Other current liabilities	421	410
TOTAL CURRENT LIABILITIES	2,885	3,512
NONCURRENT LIABILITIES
Obligations under capital leases	2	2
Provision for injuries and damages	145	141
Pensions and retiree benefits	3,985	4,220
Superfund and other environmental costs	425	433
Asset retirement obligations	160	158
Fair value of derivative liabilities	8	11
Other noncurrent liabilities	116	115
TOTAL NONCURRENT LIABILITIES	4,841	5,080
DEFERRED CREDITS AND REGULATORY LIABILITIES
Deferred income taxes and investment tax credits	7,734	7,452
Regulatory liabilities	1,110	1,077
Other deferred credits	57	67
TOTAL DEFERRED CREDITS AND REGULATORY LIABILITIES	8,901	8,596
LONG-TERM DEBT	9,640	9,145
COMMON SHAREHOLDER'S EQUITY (See Statement of Common Shareholder's Equity)	10,647	10,552
TOTAL LIABILITIES AND SHAREHOLDER'S EQUITY	36,914	36,885
CECONY [Member] | Electric Transmission [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	21,240	21,079
CECONY [Member] | Gas Transmission [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	4,619	4,547
CECONY [Member] | Steam Plant [Member]
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	$ 2,068	$ 2,049