Consolidated Edison Co Of New York 10-K 16 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2016	Jan. 31, 2017	Jun. 30, 2016
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Trading Symbol	ED
Entity Registrant Name	CONSOLIDATED EDISON INC
Entity Central Index Key	1,047,862
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		305,059,148
Entity Public Float			$ 24.5
CECONY
Document Information [Line Items]
Entity Registrant Name	CONSOLIDATED EDISON CO OF NEW YORK INC
Entity Central Index Key	23,632
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer

Consolidated Income Statement

Consolidated Income Statement - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING REVENUES
Electric	$ 8,741	$ 8,832	$ 9,114
Gas	1,692	1,709	1,933
Steam	551	629	628
Non-utility	1,091	1,384	1,244
TOTAL OPERATING REVENUES	12,075	12,554	12,919
OPERATING EXPENSES
Purchased power	2,439	2,973	3,417
Fuel	172	248	285
Gas purchased for resale	477	495	811
Other operations and maintenance	3,269	3,344	3,294
Depreciation and amortization	1,216	1,130	1,071
Taxes, other than income taxes	2,031	1,937	1,877
TOTAL OPERATING EXPENSES	9,604	10,127	10,755
Gain on sale of retail electric supply business and solar electric production projects	104	0	45
OPERATING INCOME	2,575	2,427	2,209
OTHER INCOME (DEDUCTIONS)
Investment and other income	91	35	54
Allowance for equity funds used during construction	10	5	2
Other deductions	(37)	(16)	(14)
TOTAL OTHER INCOME (DEDUCTIONS)	64	24	42
INCOME BEFORE INTEREST AND INCOME TAX EXPENSE	2,639	2,451	2,251
INTEREST EXPENSE
Interest on long-term debt	678	632	587
Other interest	24	24	5
Allowance for borrowed funds used during construction	(6)	(3)	(1)
NET INTEREST EXPENSE	696	653	591
INCOME BEFORE INCOME TAX EXPENSE	1,943	1,798	1,660
INCOME TAX EXPENSE	698	605	568
NET INCOME	$ 1,245	$ 1,193	$ 1,092
Net income per common share — basic (dollars per share)	$ 4.15	$ 4.07	$ 3.73
Net income per common share — diluted (dollars per share)	4.12	4.05	3.71
DIVIDENDS DECLARED PER COMMON SHARE (dollars per share)	$ 2.68	$ 2.60	$ 2.52
AVERAGE NUMBER OF SHARES OUTSTANDING — BASIC (IN MILLIONS)	300.4	293	292.9
AVERAGE NUMBER OF SHARES OUTSTANDING — DILUTED (IN MILLIONS)	301.9	294.4	294
CECONY
OPERATING REVENUES
Electric	$ 8,106	$ 8,172	$ 8,437
Gas	1,508	1,527	1,721
Steam	551	629	628
TOTAL OPERATING REVENUES	10,165	10,328	10,786
OPERATING EXPENSES
Purchased power	1,568	1,719	2,091
Fuel	172	248	285
Gas purchased for resale	319	337	609
Other operations and maintenance	2,806	2,881	2,873
Depreciation and amortization	1,106	1,040	991
Taxes, other than income taxes	1,932	1,856	1,798
TOTAL OPERATING EXPENSES	7,903	8,081	8,647
OPERATING INCOME	2,262	2,247	2,139
OTHER INCOME (DEDUCTIONS)
Investment and other income	8	5	22
Allowance for equity funds used during construction	8	4	1
Other deductions	(16)	(14)	(12)
TOTAL OTHER INCOME (DEDUCTIONS)	0	(5)	11
INCOME BEFORE INTEREST AND INCOME TAX EXPENSE	2,262	2,242	2,150
INTEREST EXPENSE
Interest on long-term debt	588	567	523
Other interest	19	19	15
Allowance for borrowed funds used during construction	(4)	(2)	(1)
NET INTEREST EXPENSE	603	584	537
INCOME BEFORE INCOME TAX EXPENSE	1,659	1,658	1,613
INCOME TAX EXPENSE	603	574	555
NET INCOME	$ 1,056	$ 1,084	$ 1,058

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
NET INCOME	$ 1,245	$ 1,193	$ 1,092
OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES
Pension and other postretirement benefit plan liability adjustments, net of taxes	7	11	(20)
TOTAL OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES	7	11	(20)
COMPREHENSIVE INCOME	1,252	1,204	1,072
CECONY
NET INCOME	1,056	1,084	1,058
OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES
Pension and other postretirement benefit plan liability adjustments, net of taxes	2	2	(5)
TOTAL OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES	2	2	(5)
COMPREHENSIVE INCOME	$ 1,058	$ 1,086	$ 1,053

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING ACTIVITIES
Net income	$ 1,245	$ 1,193	$ 1,092
PRINCIPAL NON-CASH CHARGES/(CREDITS) TO INCOME
Depreciation and amortization	1,216	1,130	1,071
Deferred income taxes	783	653	518
Rate case amortization and accruals	(210)	(52)	121
Common equity component of allowance for funds used during construction	(10)	(5)	(2)
Net derivative (gains)/losses	(6)	3	128
Pre-tax gain on sale of retail electric supply business and solar electric production projects	(104)	0	(45)
Other non-cash items, net	142	77	(35)
CHANGES IN ASSETS AND LIABILITIES
Accounts receivable - customers	(69)	96	44
Materials and supplies, including fuel oil and gas in storage	13	22	(10)
Other receivables and other current assets	54	(27)	316
Income taxes receivable	87	58	(224)
Prepayments	20	(14)	(27)
Accounts payable	29	(79)	(9)
Pensions and retiree benefits obligations, net	609	756	822
Pensions and retiree benefits contributions	(515)	(756)	(584)
Accrued taxes	2	(10)	(404)
Accrued interest	14	4	(113)
Superfund and environmental remediation costs, net	69	22	28
Distributions from equity investments	68	31	0
System benefit charge	244	38	(37)
Deferred charges, noncurrent assets and other regulatory assets	(97)	(111)	(361)
Deferred credits and other regulatory liabilities	(68)	182	498
Other current and noncurrent liabilities	(57)	66	44
NET CASH FLOWS FROM OPERATING ACTIVITIES	3,459	3,277	2,831
INVESTING ACTIVITIES
Utility construction expenditures	(2,835)	(2,562)	(2,239)
Cost of removal less salvage	(206)	(219)	(216)
Non-utility construction expenditures	(845)	(492)	(180)
Proceeds from grants related to solar electric production projects	0	0	36
Proceeds from sale of assets	252	0	108
Restricted cash	(17)	(13)	15
Proceeds from the transfer of assets to NY Transco	122	0	0
Other investing activities	31	(72)	10
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(4,976)	(3,657)	(2,759)
FINANCING ACTIVITIES
Net (payment)/issuance of short-term debt	(475)	729	(651)
Issuance of long-term debt	2,590	1,147	1,850
Retirement of long-term debt	(735)	(500)	(480)
Debt issuance costs	(24)	(15)	(17)
Common stock dividends	(763)	(733)	(739)
Issuance of common shares - public offering	702	0	0
Issuance of common shares for stock plans, net of repurchases	51	1	(10)
Distribution to noncontrolling interest	(1)	0	0
NET CASH FLOWS FROM/(USED IN) FINANCING ACTIVITIES	1,345	629	(47)
CASH AND TEMPORARY CASH INVESTMENTS:
NET CHANGE FOR THE PERIOD	(172)	249	25
BALANCE AT BEGINNING OF PERIOD	944	699	674
BALANCE AT END OF PERIOD	772	948	699
LESS: CHANGE IN CASH BALANCES HELD FOR SALE	(4)	4	0
BALANCE AT END OF PERIOD EXCLUDING HELD FOR SALE	776	944	699
Cash paid/(received) during the period for:
Interest	664	597	561
Income taxes	(180)	(36)	633
SUPPLEMENTAL DISCLOSURE OF NON-CASH INFORMATION
Construction expenditures in accounts payable	388	279	179
Issuance of common shares for dividend reinvestment	46	28	11
Debt assumed with business acquisitions	195	0	0
Electric and Gas Transmission Projects
INVESTING ACTIVITIES
Investments in/acquisitions of projects	(1,076)	0	0
Renewable Electric Production Projects
INVESTING ACTIVITIES
Investments in/acquisitions of projects	(402)	(299)	(293)
CECONY
OPERATING ACTIVITIES
Net income	1,056	1,084	1,058
PRINCIPAL NON-CASH CHARGES/(CREDITS) TO INCOME
Depreciation and amortization	1,106	1,040	991
Deferred income taxes	545	449	331
Rate case amortization and accruals	(227)	(74)	102
Common equity component of allowance for funds used during construction	(8)	(4)	(1)
Other non-cash items, net	(31)	(27)	(33)
CHANGES IN ASSETS AND LIABILITIES
Accounts receivable - customers	(23)	87	59
Materials and supplies, including fuel oil and gas in storage	18	24	(12)
Other receivables and other current assets	(11)	38	48
Accounts receivables from affiliated companies	81	(58)	(13)
Prepayments	13	13	(24)
Accounts payable	20	(51)	(57)
Accounts payable to affiliated companies	(2)	(11)	(22)
Pensions and retiree benefits obligations, net	579	714	742
Pensions and retiree benefits contributions	(476)	(703)	(544)
Accrued taxes	1	3	0
Accrued taxes to affiliated companies	117	(8)	(403)
Accrued interest	(7)	1	(22)
Superfund and environmental remediation costs, net	79	19	32
System benefit charge	221	38	(38)
Deferred charges, noncurrent assets and other regulatory assets	(172)	(150)	(334)
Deferred credits and other regulatory liabilities	179	379	475
Other current and noncurrent liabilities	(20)	16	95
NET CASH FLOWS FROM OPERATING ACTIVITIES	3,038	2,819	2,430
INVESTING ACTIVITIES
Utility construction expenditures	(2,672)	(2,410)	(2,094)
Cost of removal less salvage	(203)	(212)	(210)
Restricted cash	14	(16)	0
Proceeds from the transfer of assets to NY Transco	122	0	0
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(2,739)	(2,638)	(2,304)
FINANCING ACTIVITIES
Net (payment)/issuance of short-term debt	(433)	583	(760)
Issuance of long-term debt	1,300	650	1,850
Retirement of long-term debt	(650)	(350)	(475)
Debt issuance costs	(13)	(7)	(17)
Capital contribution by parent	100	13	0
Dividend to parent	(744)	(872)	(712)
NET CASH FLOWS FROM/(USED IN) FINANCING ACTIVITIES	(440)	17	(114)
CASH AND TEMPORARY CASH INVESTMENTS:
NET CHANGE FOR THE PERIOD	(141)	198	12
BALANCE AT BEGINNING OF PERIOD	843	645	633
BALANCE AT END OF PERIOD EXCLUDING HELD FOR SALE	702	843	645
Cash paid/(received) during the period for:
Interest	581	554	504
Income taxes	(162)	163	748
SUPPLEMENTAL DISCLOSURE OF NON-CASH INFORMATION
Construction expenditures in accounts payable	$ 295	$ 210	$ 151

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
CURRENT ASSETS
Cash and temporary cash investments	$ 776	$ 944
Accounts receivable - customers, less allowance for uncollectible accounts	1,106	1,052
Other receivables, less allowance for uncollectible accounts	195	304
Income taxes receivable	79	166
Accrued unbilled revenue	447	360
Fuel oil, gas in storage, materials and supplies, at average cost	339	350
Prepayments	159	177
Regulatory assets	100	132
Assets held for sale	0	157
Other current assets	205	194
TOTAL CURRENT ASSETS	3,406	3,836
INVESTMENTS	1,921	884
UTILITY PLANT, AT ORIGINAL COST
General	2,719	2,622
TOTAL	40,411	38,174
Less: Accumulated depreciation	8,541	8,044
Net	31,870	30,130
Construction work in progress	1,175	1,003
NET UTILITY PLANT	33,045	31,133
NON-UTILITY PLANT
Non-utility property, less accumulated depreciation	1,482	832
Construction work in progress	689	244
NET PLANT	35,216	32,209
OTHER NONCURRENT ASSETS
Goodwill	428	429
Intangible assets, less accumulated amortization of $6 and $4 in 2016 and 2015, respectively	124	2
Regulatory assets	7,024	8,096
Other deferred charges and noncurrent assets	136	186
TOTAL OTHER NONCURRENT ASSETS	7,712	8,713
TOTAL ASSETS	48,255	45,642
CURRENT LIABILITIES
Long-term debt due within one year	39	739
Notes payable	1,054	1,529
Accounts payable	1,147	1,008
Customer deposits	352	354
Accrued taxes	64	62
Accrued interest	150	136
Accrued wages	101	97
Fair value of derivative liabilities	77	66
Regulatory liabilities	128	115
Liabilities held for sale	0	89
System benefit charge	434	190
Other current liabilities	297	335
TOTAL CURRENT LIABILITIES	3,843	4,720
NONCURRENT LIABILITIES
Provision for injuries and damages	160	185
Pensions and retiree benefits	1,847	2,911
Superfund and other environmental costs	753	765
Asset retirement obligations	246	242
Fair value of derivative liabilities	40	39
Deferred income taxes and unamortized investment tax credits	10,205	9,537
Regulatory liabilities	1,905	1,977
Other deferred credits and noncurrent liabilities	215	199
TOTAL NONCURRENT LIABILITIES	15,371	15,855
LONG-TERM DEBT	14,735	12,006
EQUITY
Common shareholders’ equity	14,298	13,052
Noncontrolling interest	8	9
TOTAL EQUITY (See Statement of Equity)	14,306	13,061
TOTAL LIABILITIES AND EQUITY	48,255	45,642
Electric
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	27,747	26,358
Gas
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	7,524	6,858
Steam
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	2,421	2,336
CECONY
CURRENT ASSETS
Cash and temporary cash investments	702	843
Accounts receivable - customers, less allowance for uncollectible accounts	1,032	987
Other receivables, less allowance for uncollectible accounts	81	70
Accrued unbilled revenue	399	327
Accounts receivable from affiliated companies	109	190
Fuel oil, gas in storage, materials and supplies, at average cost	270	288
Prepayments	100	113
Regulatory assets	90	121
Other current assets	97	133
TOTAL CURRENT ASSETS	2,880	3,072
INVESTMENTS	315	286
UTILITY PLANT, AT ORIGINAL COST
General	2,490	2,411
TOTAL	37,847	35,766
Less: Accumulated depreciation	7,836	7,378
Net	30,011	28,388
Construction work in progress	1,104	922
NET UTILITY PLANT	31,115	29,310
NON-UTILITY PLANT
Non-utility property, less accumulated depreciation	4	5
NET PLANT	31,119	29,315
OTHER NONCURRENT ASSETS
Goodwill	245	245
Regulatory assets	6,473	7,482
Other deferred charges and noncurrent assets	69	75
TOTAL OTHER NONCURRENT ASSETS	6,542	7,557
TOTAL ASSETS	40,856	40,230
CURRENT LIABILITIES
Long-term debt due within one year	0	650
Notes payable	600	1,033
Accounts payable	876	771
Accounts payable to affiliated companies	10	12
Customer deposits	336	339
Accrued taxes	50	49
Accrued taxes to affiliated companies	119	2
Accrued interest	111	118
Accrued wages	91	88
Fair value of derivative liabilities	66	50
Regulatory liabilities	90	84
System benefit charge	398	177
Other current liabilities	242	266
TOTAL CURRENT LIABILITIES	2,989	3,639
NONCURRENT LIABILITIES
Provision for injuries and damages	154	178
Pensions and retiree benefits	1,544	2,565
Superfund and other environmental costs	655	665
Asset retirement obligations	227	234
Fair value of derivative liabilities	33	36
Deferred income taxes and unamortized investment tax credits	9,450	8,755
Regulatory liabilities	1,712	1,789
Other deferred credits and noncurrent liabilities	190	167
TOTAL NONCURRENT LIABILITIES	13,965	14,389
LONG-TERM DEBT	12,073	10,787
EQUITY
Common shareholders’ equity	11,829	11,415
TOTAL LIABILITIES AND EQUITY	40,856	40,230
CECONY | Electric
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	26,122	24,828
CECONY | Gas
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	6,814	6,191
CECONY | Steam
UTILITY PLANT, AT ORIGINAL COST
Utility plant, at original cost	$ 2,421	$ 2,336

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Accounts receivable - customers, allowance for uncollectible accounts	$ 69	$ 85
Other receivables, allowance for uncollectible accounts	14	11
Non-utility property, accumulated depreciation	140	95
Intangible assets, accumulated amortization	6	4
CECONY
Accounts receivable - customers, allowance for uncollectible accounts	65	80
Other receivables, allowance for uncollectible accounts	13	11
Non-utility property, accumulated depreciation	$ 25	$ 25

Consolidated Statement of Share

Consolidated Statement of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Capital Stock Expense	Accumulated Other Comprehensive Income/(Loss)	Noncontrolling Interest	CECONY	CECONYCommon Stock	CECONYAdditional Paid-In Capital	CECONYRetained Earnings	CECONYRepurchased Con Edison Stock	CECONYCapital Stock Expense	CECONYAccumulated Other Comprehensive Income/(Loss)
BALANCE AS OF BEGINNING OF PERIOD (in shares) at Dec. 31, 2013		293,000,000								235,000,000
BALANCE AS OF BEGINNING OF PERIOD at Dec. 31, 2013	$ 12,245	$ 32	$ 4,995	$ 8,338	$ (1,034)	$ (61)	$ (25)	$ 0
BALANCE AS OF BEGINNING OF PERIOD at Dec. 31, 2013									$ 10,847	$ 589	$ 4,234	$ 7,053	$ (962)	$ (61)	$ (6)
TREASURY STOCK, BALANCE AS OF BEGINNING OF PERIOD (in shares) at Dec. 31, 2013					23,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,092			1,092					1,058			1,058
Common stock dividends	(739)			(739)					(712)			(712)
Issuance of common shares for stock plans, net of repurchases (in shares)		0			0
Issuance of common shares for stock plans, net of repurchases	(2)		(4)		$ 2
Other comprehensive income (loss)	(20)						(20)		(5)						(5)
Noncontrolling interest	9							9
BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2014		293,000,000								235,000,000
BALANCE AS OF END OF PERIOD at Dec. 31, 2014	12,585	$ 32	4,991	8,691	$ (1,032)	(61)	(45)	9							(11)
BALANCE AS OF END OF PERIOD at Dec. 31, 2014									11,188	$ 589	4,234	7,399	(962)	(61)	(11)
TREASURY STOCK, BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2014					23,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,193			1,193					1,084			1,084
Common stock dividends	(761)			(761)					(872)			(872)
Issuance of common shares for stock plans, net of repurchases (in shares)		0			0
Issuance of common shares for stock plans, net of repurchases	33		39		$ (6)
Capital contribution by parent									13		13
Other comprehensive income (loss)	11						11		2						2
Noncontrolling interest	0							0
BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2015		293,000,000								235,000,000
BALANCE AS OF END OF PERIOD at Dec. 31, 2015	13,061	$ 32	5,030	9,123	$ (1,038)	(61)	(34)	9							(9)
BALANCE AS OF END OF PERIOD at Dec. 31, 2015	13,052								11,415	$ 589	4,247	7,611	(962)	(61)	(9)
TREASURY STOCK, BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2015					23,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,245			1,245					1,056			1,056
Common stock dividends	(809)			(809)					(744)			(744)
Issuance of common shares - public offering (in shares)		10,000,000
Issuance of common shares - public offering	702	$ 1	723			(22)
Issuance of common shares for stock plans (in shares)		2,000,000
Issuance of common shares for stock plans	101		101
Capital contribution by parent									100		100
Other comprehensive income (loss)	7						7		$ 2						2
Noncontrolling interest	(1)							(1)
BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2016		305,000,000							21,976,200	235,000,000
BALANCE AS OF END OF PERIOD at Dec. 31, 2016	14,306	$ 33	$ 5,854	$ 9,559	$ (1,038)	$ (83)	$ (27)	$ 8							(7)
BALANCE AS OF END OF PERIOD at Dec. 31, 2016	$ 14,298								$ 11,829	$ 589	$ 4,347	$ 7,923	$ (962)	$ (61)	$ (7)
TREASURY STOCK, BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2016					23,000,000

Consolidated Statement of Capit

Consolidated Statement of Capitalization - USD ($) shares in Millions, $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule of Capitalization, Equity [Line Items]
TOTAL EQUITY BEFORE ACCUMULATED OTHER COMPREHENSIVE LOSS (in shares)	305	293
TOTAL EQUITY BEFORE ACCUMULATED OTHER COMPREHENSIVE LOSS	$ 14,325	$ 13,086
Pension plan liability adjustments, net of taxes	(24)	(31)
Unrealized gains/(losses) on derivatives qualified as cash flow hedges, less reclassification adjustment for gains/(losses) included in net income and reclassification adjustment for unrealized losses included in regulatory assets, net of taxes	(3)	(3)
TOTAL ACCUMULATED OTHER COMPREHENSIVE LOSS, NET OF TAXES	(27)	(34)
Equity	14,298	13,052
Noncontrolling interest	8	9
TOTAL EQUITY (See Statement of Equity)	$ 14,306	$ 13,061
CECONY
Schedule of Capitalization, Equity [Line Items]
TOTAL EQUITY BEFORE ACCUMULATED OTHER COMPREHENSIVE LOSS (in shares)	235	235
TOTAL EQUITY BEFORE ACCUMULATED OTHER COMPREHENSIVE LOSS	$ 11,836	$ 11,424
Pension plan liability adjustments, net of taxes	(4)	(6)
Unrealized gains/(losses) on derivatives qualified as cash flow hedges, less reclassification adjustment for gains/(losses) included in net income and reclassification adjustment for unrealized losses included in regulatory assets, net of taxes	(3)	(3)
TOTAL ACCUMULATED OTHER COMPREHENSIVE LOSS, NET OF TAXES	(7)	(9)
Equity	11,829	11,415
TOTAL SHAREHOLDER’S EQUITY (See Statement of Shareholder’s Equity)	$ 11,829	$ 11,415

Consolidated Statement of Capi9

Consolidated Statement of Capitalization - Long-term Debt - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Schedule of Capitalization, Long-term Debt [Line Items]
Other long-term debt		$ 317	$ 323
Unamortized debt expense		(107)	(91)
Unamortized debt discount		(27)	(22)
TOTAL		14,774	12,745
Long-term debt - Variable rate term loan		400	0
Less: Long-term debt due within one year		39	739
TOTAL LONG-TERM DEBT		14,735	12,006
TOTAL CAPITALIZATION		29,033	25,058
CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Unamortized debt expense		(87)	(78)
Unamortized debt discount		(26)	(21)
TOTAL		12,073	11,437
Less: Long-term debt due within one year		0	650
TOTAL LONG-TERM DEBT		12,073	10,787
TOTAL CAPITALIZATION		23,902	22,202
Coram
Schedule of Capitalization, Long-term Debt [Line Items]
TOTAL		$ 180	0
Coram | Maximum
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.52%
Texas Solar 4
Schedule of Capitalization, Long-term Debt [Line Items]
TOTAL		$ 64	64
Texas Solar 4 | Minimum
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.95%
Texas Solar 4 | Maximum
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.25%
California Solar 2
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		3.94%
TOTAL		$ 114	115
California Solar 3
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.07%
TOTAL		$ 95	0
Texas Solar 5
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.53%
TOTAL		$ 158	159
Texas Solar 7
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.21%
TOTAL		$ 218	0
Other project debt
Schedule of Capitalization, Long-term Debt [Line Items]
TOTAL		16	1
Project Debt
Schedule of Capitalization, Long-term Debt [Line Items]
TOTAL		845	339
Debentures
Schedule of Capitalization, Long-term Debt [Line Items]
TOTAL		12,260	11,110
Debentures | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
TOTAL		$ 11,100	10,450
Debentures | Debenture Series 2006A, 5.45% Due 2016
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.45%
TOTAL		$ 0	75
Debentures | Debenture Series 2006C, 5.50% Due 2016
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.50%
TOTAL		$ 0	400
Debentures | Debenture Series 2006C, 5.50% Due 2016 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.50%
TOTAL		$ 0	400
Debentures | Debenture Series 2006D, 5.30% Due 2016
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.30%
TOTAL		$ 0	250
Debentures | Debenture Series 2006D, 5.30% Due 2016 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.30%
TOTAL		$ 0	250
Debentures | Debenture Series 2008A, 5.85% Due 2018
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.85%
TOTAL		$ 600	600
Debentures | Debenture Series 2008A, 5.85% Due 2018 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.85%
TOTAL		$ 600	600
Debentures | Debenture Series 2008A, 6.15% Due 2018
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		6.15%
TOTAL		$ 50	50
Debentures | Debenture Series 2008C, 7.125% Due 2018
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		7.125%
TOTAL		$ 600	600
Debentures | Debenture Series 2008C, 7.125% Due 2018 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		7.125%
TOTAL		$ 600	600
Debentures | Debenture Series 2009A, 4.96% Due 2019
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.96%
TOTAL		$ 60	60
Debentures | Debenture Series 2009B, 6.65% Due 2019
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		6.65%
TOTAL		$ 475	475
Debentures | Debenture Series 2009B, 6.65% Due 2019 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		6.65%
TOTAL		$ 475	475
Debentures | Debenture Series 2010A, 4.45% Due 2020
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.45%
TOTAL		$ 350	350
Debentures | Debenture Series 2010A, 4.45% Due 2020 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.45%
TOTAL		$ 350	350
Debentures | Debenture Series 2016A, 2.00% Due 2021
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		2.00%
TOTAL		$ 500	0
Debentures | Debenture Series 2014B, 3.30% Due 2024
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		3.30%
TOTAL		$ 250	250
Debentures | Debenture Series 2014B, 3.30% Due 2024 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		3.30%
TOTAL		$ 250	250
Debentures | Debenture Series 2016B, 2.90% Due 2026
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		2.90%
TOTAL		$ 250	0
Debentures | Debenture Series 2016B, 2.90% Due 2026 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		2.90%
TOTAL		$ 250	0
Debentures | Debenture Series 1997F, 6.50% Due 2027
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		6.50%
TOTAL		$ 80	80
Debentures | Debenture Series 2003A, 5.875% Due 2033
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.875%
TOTAL		$ 175	175
Debentures | Debenture Series 2003A, 5.875% Due 2033 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.875%
TOTAL		$ 175	175
Debentures | Debenture Series 2003C, 5.10% Due 2033
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.10%
TOTAL		$ 200	200
Debentures | Debenture Series 2003C, 5.10% Due 2033 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.10%
TOTAL		$ 200	200
Debentures | Debenture Series 2004B, 5.70% Due 2034
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.70%
TOTAL		$ 200	200
Debentures | Debenture Series 2004B, 5.70% Due 2034 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.70%
TOTAL		$ 200	200
Debentures | Debenture Series 2005A, 5.30% Due 2035
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.30%
TOTAL		$ 350	350
Debentures | Debenture Series 2005A, 5.30% Due 2035 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.30%
TOTAL		$ 350	350
Debentures | Debenture Series 2005B, 5.25% Due 2035
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.25%
TOTAL		$ 125	125
Debentures | Debenture Series 2005B, 5.25% Due 2035 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.25%
TOTAL		$ 125	125
Debentures | Debenture Series 2006A, 5.85% Due 2036
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.85%
TOTAL		$ 400	400
Debentures | Debenture Series 2006A, 5.85% Due 2036 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.85%
TOTAL		$ 400	400
Debentures | Debenture Series 2006B, 6.20% Due 2036
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		6.20%
TOTAL		$ 400	400
Debentures | Debenture Series 2006B, 6.20% Due 2036 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		6.20%
TOTAL		$ 400	400
Debentures | Debenture Series 2006E, 5.70% Due 2036
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.70%
TOTAL		$ 250	250
Debentures | Debenture Series 2006E, 5.70% Due 2036 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.70%
TOTAL		$ 250	250
Debentures | Debenture Series 2007A, 6.30% Due 2037
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		6.30%
TOTAL		$ 525	525
Debentures | Debenture Series 2007A, 6.30% Due 2037 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		6.30%
TOTAL		$ 525	525
Debentures | Debenture Series 2008B, 6.75% Due 2038
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		6.75%
TOTAL		$ 600	600
Debentures | Debenture Series 2008B, 6.75% Due 2038 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		6.75%
TOTAL		$ 600	600
Debentures | Debenture Series 2009B, 6.00% Due 2039
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		6.00%
TOTAL		$ 60	60
Debentures | Debenture Series 2009C, 5.50% Due 2039
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.50%
TOTAL		$ 600	600
Debentures | Debenture Series 2009C, 5.50% Due 2039 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.50%
TOTAL		$ 600	600
Debentures | Debenture Series 2010B, 5.70% Due 2040
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.70%
TOTAL		$ 350	350
Debentures | Debenture Series 2010B, 5.70% Due 2040 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.70%
TOTAL		$ 350	350
Debentures | Debenture Series 2010B, 5.50% Due 2040
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		5.50%
TOTAL		$ 115	115
Debentures | Debenture Series 2012A, 4.20% Due 2042
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.20%
TOTAL		$ 400	400
Debentures | Debenture Series 2012A, 4.20% Due 2042 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.20%
TOTAL		$ 400	400
Debentures | Debenture Series 2013A, 3.95% Due 2043
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		3.95%
TOTAL		$ 700	700
Debentures | Debenture Series 2013A, 3.95% Due 2043 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		3.95%
TOTAL		$ 700	700
Debentures | Debenture Series 2014A, 4.45% Due 2044
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.45%
TOTAL		$ 850	850
Debentures | Debenture Series 2014A, 4.45% Due 2044 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.45%
TOTAL		$ 850	850
Debentures | Debenture Series 2015A, 4.50% due 2045
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.50%
TOTAL		$ 650	650
Debentures | Debenture Series 2015A, 4.50% due 2045 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.50%
TOTAL		$ 650	650
Debentures | Debenture Series 2015A, 4.95% due 2045
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.95%
TOTAL		$ 120	120
Debentures | Debenture Series 2015B, 4.69% due 2045
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.69%
TOTAL		$ 100	100
Debentures | Debenture Series 2016A, 3.85% Due 2046
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		3.85%
TOTAL		$ 550	0
Debentures | Debenture Series 2016A, 3.85% Due 2046 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		3.85%
TOTAL		$ 550	0
Debentures | Debenture Series 2016A. 3.88% Due 2046
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		3.88%
TOTAL		$ 75	0
Debentures | Debenture Series 2014C, 4.625% Due 2054
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.625%
TOTAL		$ 750	750
Debentures | Debenture Series 2014C, 4.625% Due 2054 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.625%
TOTAL		$ 750	750
Debentures | Debenture Series 2016C, 4.30% Due 2056
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.30%
TOTAL		$ 500
Debentures | Debenture Series 2016C, 4.30% Due 2056 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		4.30%
TOTAL		$ 500	0
Tax-Exempt Debt
Schedule of Capitalization, Long-term Debt [Line Items]
TOTAL	[1]	1,086	1,086
Tax-Exempt Debt | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
TOTAL		$ 1,086	1,086
Tax-Exempt Debt | Tax Exempt Debt Series 2004B Series 1, 0.98% due 2032
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate	[1]	0.98%
TOTAL	[1]	$ 127	127
Tax-Exempt Debt | Tax Exempt Debt Series 2004B Series 1, 0.98% due 2032 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		0.98%
TOTAL		$ 127	127
Tax-Exempt Debt | Tax Exempt Debt Series 1999A, 0.98% Due 2034
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate	[1]	0.98%
TOTAL	[1]	$ 293	293
Tax-Exempt Debt | Tax Exempt Debt Series 1999A, 0.98% Due 2034 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		0.98%
TOTAL		$ 293	293
Tax-Exempt Debt | Tax Exempt Debt Series 2004B Series 2, 0.998% Due 2035
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate	[1]	0.998%
TOTAL	[1]	$ 20	20
Tax-Exempt Debt | Tax Exempt Debt Series 2004B Series 2, 0.998% Due 2035 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		0.998%
TOTAL		$ 20	20
Tax-Exempt Debt | Tax Exempt Debt Series 2001B, 1.134% due 2036
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate	[1]	1.134%
TOTAL	[1]	$ 98	98
Tax-Exempt Debt | Tax Exempt Debt Series 2001B, 1.134% due 2036 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		1.134%
TOTAL		$ 98	98
Tax-Exempt Debt | Tax Exempt Debt Series 2010A, 0.745% due 2036
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate	[1]	0.745%
TOTAL	[1]	$ 225	225
Tax-Exempt Debt | Tax Exempt Debt Series 2010A, 0.745% due 2036 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		0.745%
TOTAL		$ 225	225
Tax-Exempt Debt | Tax Exempt Debt Series 2004A, 0.963% due 2039
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate	[1]	0.963%
TOTAL	[1]	$ 98	98
Tax-Exempt Debt | Tax Exempt Debt Series 2004A, 0.963% due 2039 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		0.963%
TOTAL		$ 98	98
Tax-Exempt Debt | Tax Exempt Debt Series 2004C, 0.74% due 2039
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate	[1]	0.74%
TOTAL	[1]	$ 99	99
Tax-Exempt Debt | Tax Exempt Debt Series 2004C, 0.74% due 2039 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		0.74%
TOTAL		$ 99	99
Tax-Exempt Debt | Tax-Exempt Debt Series 2005A, 0.723% Due 2039
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate	[1]	0.723%
TOTAL	[1]	$ 126	126
Tax-Exempt Debt | Tax-Exempt Debt Series 2005A, 0.723% Due 2039 | CECONY
Schedule of Capitalization, Long-term Debt [Line Items]
Interest Rate		0.723%
TOTAL		$ 126	$ 126
[1]	Rates are to be reset weekly or by auction held every 35 days; December 31, 2016 rates shown.

General

General	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General	General These combined notes accompany and form an integral part of the separate consolidated financial statements of each of the two separate registrants: Consolidated Edison, Inc. and its subsidiaries (Con Edison) and Consolidated Edison Company of New York, Inc. and its subsidiaries (CECONY). CECONY is a subsidiary of Con Edison and as such its financial condition and results of operations and cash flows, which are presented separately in the CECONY consolidated financial statements, are also consolidated, along with those of Orange and Rockland Utilities, Inc. (O&R), Con Edison Clean Energy Businesses, Inc. (together with its subsidiaries, the Clean Energy Businesses) and Con Edison Transmission, Inc. (together with its subsidiaries, Con Edison Transmission) in Con Edison’s consolidated financial statements. The term “Utilities” is used in these notes to refer to CECONY and O&R. As used in these notes, the term “Companies” refers to Con Edison and CECONY and, except as otherwise noted, the information in these combined notes relates to each of the Companies. However, CECONY makes no representation as to information relating to Con Edison or the subsidiaries of Con Edison other than itself. Con Edison has two regulated utility subsidiaries: CECONY and O&R. CECONY provides electric service and gas service in New York City and Westchester County. The company also provides steam service in parts of Manhattan. O&R, along with its regulated utility subsidiary, provides electric service in southeastern New York and northern New Jersey and gas service in southeastern New York. The Clean Energy Businesses, Inc. has three subsidiaries: Consolidated Edison Development, Inc. (Con Edison Development), a company that develops, owns and operates renewable and energy infrastructure projects; Consolidated Edison Energy, Inc. (Con Edison Energy), a company that provides energy-related products and services to wholesale customers; and Consolidated Edison Solutions, Inc. (Con Edison Solutions), a company that provides energy-related products and services to retail customers. Con Edison Transmission, Inc. invests in electric transmission facilities through its subsidiary, Consolidated Edison Transmission, LLC (CET Electric), and invests in gas pipeline and storage facilities through its subsidiary Con Edison Gas Pipeline and Storage, LLC (CET Gas). See Note U.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principles of Consolidation The Companies’ consolidated financial statements include the accounts of their respective majority-owned subsidiaries, and variable interest entities (see Note Q), as required. All intercompany balances and transactions have been eliminated. Accounting Policies The accounting policies of Con Edison and its subsidiaries conform to generally accepted accounting principles in the United States of America (GAAP). For the Utilities, these accounting principles include the accounting rules for regulated operations and the accounting requirements of the Federal Energy Regulatory Commission (FERC) and the state regulators having jurisdiction. The accounting rules for regulated operations specify the economic effects that result from the causal relationship of costs and revenues in the rate-regulated environment and how these effects are to be accounted for by a regulated enterprise. Revenues intended to cover some costs may be recorded either before or after the costs are incurred. If regulation provides assurance that incurred costs will be recovered in the future, these costs would be recorded as deferred charges or “regulatory assets” under the accounting rules for regulated operations. If revenues are recorded for costs that are expected to be incurred in the future, these revenues would be recorded as deferred credits or “regulatory liabilities” under the accounting rules for regulated operations. The Utilities’ principal regulatory assets and liabilities are detailed in Note B. The Utilities are receiving or being credited with a return on all of their regulatory assets for which a cash outflow has been made, and are paying or being charged with a return on all of their regulatory liabilities for which a cash inflow has been received. The Utilities’ regulatory assets and liabilities will be recovered from customers, or applied for customer benefit, in accordance with rate provisions approved by the applicable state regulators. Other significant accounting policies of the Companies are referenced below in this Note A and in the notes that follow. Plant and Depreciation Utility Plant Utility plant is stated at original cost. The cost of repairs and maintenance is charged to expense and the cost of betterments is capitalized. The capitalized cost of additions to utility plant includes indirect costs such as engineering, supervision, payroll taxes, pensions, other benefits and an allowance for funds used during construction (AFUDC). The original cost of property is charged to expense over the estimated useful lives of the assets. Upon retirement, the original cost of property is charged to accumulated depreciation. See Note R. Rates used for AFUDC include the cost of borrowed funds and a reasonable rate of return on the Utilities’ own funds when so used, determined in accordance with regulations of the FERC or the state public utility regulatory authority having jurisdiction. The rate is compounded semiannually, and the amounts applicable to borrowed funds are treated as a reduction of interest charges, while the amounts applicable to the Utilities’ own funds are credited to other income (deductions). The AFUDC rates for CECONY were 4.7 percent , 4.4 percent and 1.6 percent for 2016 , 2015 and 2014 , respectively. The AFUDC rates for O&R were 3.5 percent , 0.4 percent and 2.6 percent for 2016 , 2015 and 2014 , respectively. The Utilities generally compute annual charges for depreciation using the straight-line method for financial statement purposes, with rates based on average service lives and net salvage factors. The average depreciation rates for CECONY were 3.1 percent for 2016 , 2015 and 2014 . The average depreciation rates for O&R were 2.9 percent , 3.0 percent and 2.9 percent for 2016 , 2015 and 2014 , respectively. The estimated lives for utility plant for CECONY range from 5 to 85 years for electric and gas, 5 to 80 years for steam and 5 to 55 years for general plant. For O&R, the estimated lives for utility plant range from 5 to 75 years for electric and gas and 5 to 50 years for general plant. At December 31, 2016 and 2015 , the capitalized cost of the Companies’ utility plant, net of accumulated depreciation, was as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Electric Generation $479 $459 $479 $459 Transmission 3,184 3,045 2,963 2,833 Distribution 18,150 17,244 17,234 16,394 Gas (a) 6,285 5,698 5,749 5,196 Steam 1,882 1,849 1,882 1,849 General 1,816 1,758 1,639 1,592 Held for future use 74 77 65 65 Construction work in progress 1,175 1,003 1,104 922 Net Utility Plant $33,045 $31,133 $31,115 $29,310 (a) Primarily distribution. Under the Utilities’ rate plans, the aggregate annual depreciation allowance in effect at December 31, 2016 was $1,176 million , including $1,106 million under CECONY’s electric, gas and steam rate plans that have been approved by the New York State Public Service Commission (NYSPSC). Non-Utility Plant Non-utility plant is stated at original cost. For Con Edison, non-utility plant consists primarily of the Clean Energy Businesses’ renewable electric production and gas storage. For the Utilities, non-utility plant consists of land and conduit for telecommunication use. Depreciation on these assets is computed using the straight-line method for financial statement purposes over their estimated useful lives, which range from 3 to 30 years . Goodwill Con Edison tests goodwill for impairment at least annually or whenever there is a triggering event. There is an option to first make a qualitative assessment of whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount before applying a two-step, quantitative goodwill impairment test. However, Con Edison has not elected to perform the qualitative assessment and exclusively applies the two-step quantitative approach. The first step of the goodwill impairment test compares the estimated fair value of a reporting unit with its carrying value, including goodwill. If the estimated fair value of a reporting unit exceeds its carrying value, goodwill of the reporting unit is considered not impaired. If the carrying value exceeds the estimated fair value of the reporting unit, the second step is performed to measure the amount of impairment loss, if any. The second step requires a calculation of the implied fair value of goodwill. In 2016, Con Edison Solutions recorded a $15 million impairment charge on goodwill. See Note K. Long-Lived and Intangible Assets Con Edison evaluates the impairment of long-lived assets and intangible assets with definite lives, based on projections of undiscounted future cash flows, whenever events or changes in circumstances indicate that the carrying amounts of such assets may not be recoverable. In the event an evaluation indicates that such cash flows cannot be expected to be sufficient to fully recover the assets, the assets are written down to their estimated fair value. In 2015, Con Edison recorded a $5 million impairment charge on the assets held for sale of Pike County Light & Power Company (Pike), a former O&R subsidiary that was sold in August 2016 (see Note U). No impairment charges on long-lived assets were recognized in 2016 or 2014 . No impairment charges on intangible assets with definite lives were recognized in 2016, 2015, or 2014. For information about the Companies' intangible assets, see Note K. Revenues The Utilities recognize and, until the sale of its retail electric supply business in September 2016 (see Note U), Con Edison Solutions recognized revenues for energy service on a monthly billing cycle basis. The Utilities defer over a 12 -month period net interruptible gas revenues, other than those authorized by the NYSPSC to be retained by the Utilities, for refund to firm gas sales and transportation customers. The Utilities accrue and Con Edison Solutions accrued revenues at the end of each month for estimated energy service not yet billed to customers. CECONY’s electric and gas rate plans and O&R’s New York electric and gas rate plans each contain a revenue decoupling mechanism under which the company’s actual energy delivery revenues are compared with the authorized delivery revenues and the difference accrued, with interest, for refund to, or recovery from, customers, as applicable. See “Rate Plans” in Note B. The NYSPSC requires utilities to record gross receipts tax revenues and expenses on a gross income statement presentation basis (i.e., included in both revenue and expense). The recovery of these taxes is generally provided for in the revenue requirement within each of the respective NYSPSC approved rate plans. Total excise taxes (inclusive of gross receipts taxes) recorded in operating revenues were as follows: For the Years Ended December 31, (Millions of Dollars) 2016 2015 2014 Con Edison $336 $354 $365 CECONY 316 331 343 For information about changes to the accounting rules for revenue recognition, see Note T. Recoverable Energy Costs The Utilities generally recover all of their prudently incurred fuel, purchased power and gas costs, including hedging gains and losses, in accordance with rate provisions approved by the applicable state public utility regulators. If the actual energy supply costs for a given month are more or less than the amounts billed to customers for that month, the difference in most cases is recoverable from or refundable to customers. Differences between actual and billed electric and steam supply costs and costs of its electric demand management programs are generally deferred for charge or refund to customers during the next billing cycle (normally within one or two months ). For the Utilities’ gas costs, differences between actual and billed gas costs during the 12-month period ending each August are charged or refunded to customers during a subsequent 12-month period. New York Independent System Operator (NYISO) The Utilities purchase electricity through the wholesale electricity market administered by the NYISO. The difference between purchased power and related costs initially billed to the Utilities by the NYISO and the actual cost of power subsequently calculated by the NYISO is refunded by the NYISO to the Utilities, or paid to the NYISO by the Utilities. The reconciliation payments or receipts are recoverable from or refundable to the Utilities’ customers. Certain other payments to or receipts from the NYISO are also subject to reconciliation, with shortfalls or amounts in excess of specified rate allowances recoverable from or refundable to customers. These include proceeds from the sale through the NYISO of transmission rights on CECONY’s transmission system (transmission congestion contracts or TCCs). Temporary Cash Investments Temporary cash investments are short-term, highly-liquid investments that generally have maturities of three months or less at the date of purchase. They are stated at cost, which approximates market. The Companies consider temporary cash investments to be cash equivalents. Investments Investments consist primarily of the investments of Con Edison Transmission and the Clean Energy Businesses that are accounted for under the equity method and the fair value of the Utilities’ supplemental retirement income plan and deferred income plan assets. The following investment assets are included in the Companies' consolidated balance sheets at December 31, 2016 and 2015: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 CET Gas investment in Stagecoach Gas Services, LLC (a) $992 $— $— $— Con Edison Development equity method investments (b) 488 574 — — Supplemental retirement income plan assets (c) 273 243 246 221 Deferred income plan assets 60 55 60 55 CET Electric investment in New York Transco, LLC 51 3 — — CET Gas investment in Mountain Valley Pipeline, LLC 48 — — — Other 9 9 9 10 Total investments $1,921 $884 $315 $286 (a) See Note U. (b) See Note Q. (c) See Note E. Pension and Other Postretirement Benefits The accounting rules for retirement benefits require an employer to recognize an asset or liability for the overfunded or underfunded status of its pension and other postretirement benefit plans. For a pension plan, the asset or liability is the difference between the fair value of the plan’s assets and the projected benefit obligation. For any other postretirement benefit plan, the asset or liability is the difference between the fair value of the plan’s assets and the accumulated postretirement benefit obligation. The accounting rules generally require employers to recognize all unrecognized prior service costs and credits and unrecognized actuarial gains and losses in accumulated other comprehensive income/(loss) (OCI), net of tax. Such amounts will be adjusted as they are subsequently recognized as components of total periodic benefit cost or income pursuant to the current recognition and amortization provisions. For the Utilities’ pension and other postretirement benefit plans, regulatory accounting treatment is generally applied in accordance with the accounting rules for regulated operations. Unrecognized prior service costs or credits and unrecognized actuarial gains and losses are recorded to regulatory assets or liabilities, rather than OCI. See Notes E and F. The total periodic benefit costs are recognized in accordance with the accounting rules for retirement benefits. Investment gains and losses are recognized in expense over a 15 -year period and other actuarial gains and losses are recognized in expense over a 10 -year period, subject to the deferral provisions in the rate plans. In accordance with the Statement of Policy issued by the NYSPSC and its current electric, gas and steam rate plans, CECONY defers for payment to or recovery from customers the difference between such expenses and the amounts for such expenses reflected in rates. Generally, O&R also defers such difference pursuant to its rate plans. See Note B. The Companies calculate the expected return on pension and other postretirement benefit plan assets by multiplying the expected rate of return on plan assets by the market-related value (MRV) of plan assets at the beginning of the year, taking into consideration anticipated contributions and benefit payments that are to be made during the year. The accounting rules allow the MRV of plan assets to be either fair value or a calculated value that recognizes changes in fair value in a systematic and rational manner over not more than five years. The Companies use a calculated value when determining the MRV of the plan assets that adjusts for 20 percent of the difference between fair value and expected MRV of plan assets. This calculated value has the effect of stabilizing variability in assets to which the Companies apply the expected return. Federal Income Tax In accordance with accounting rules for income taxes, the Companies have recorded an accumulated deferred federal income tax liability at current tax rates for temporary differences between the book and tax basis of assets and liabilities. In accordance with rate plans, the Utilities have recovered amounts from customers for a portion of the tax liability they will pay in the future as a result of the reversal or “turn-around” of these temporary differences. As to the remaining tax liability, the Utilities have established regulatory assets for the net revenue requirements to be recovered from customers for the related future tax expense. See Notes B and L. In 1993, the NYSPSC issued a Policy Statement approving accounting procedures consistent with accounting rules for income taxes and providing assurances that these future increases in taxes will be recoverable in rates. See Note L. Accumulated deferred investment tax credits are amortized ratably over the lives of the related properties and applied as a reduction to future federal income tax expense. Con Edison and its subsidiaries file a consolidated federal income tax return. The consolidated income tax liability is allocated to each member of the consolidated group using the separate return method. Each member pays or receives an amount based on its own taxable income or loss in accordance with a consolidated tax allocation agreement. Tax loss and tax credit carryforwards are allocated among members in accordance with consolidated tax return regulations. State Income Tax Con Edison and its subsidiaries file a combined New York State Corporation Business Franchise Tax Return. Similar to a federal consolidated income tax return, the income of all entities in the combined group is subject to New York State taxation, after adjustments for differences between federal and New York law and apportionment of income among the states in which the company does business. Each member’s share of the New York State tax is based on its own New York State taxable income or loss. Research and Development Costs Research and development costs are charged to operating expenses as incurred. Research and development costs were as follows: For the Years Ended December 31, (Millions of Dollars) 2016 2015 2014 Con Edison $24 $23 $22 CECONY 22 22 20 Reclassification Certain prior year amounts have been reclassified to conform with the current year presentation. Earnings Per Common Share Con Edison presents basic and diluted earnings per share on the face of its consolidated income statement. Basic earnings per share (EPS) are calculated by dividing earnings available to common shareholders (“Net income” on Con Edison’s consolidated income statement) by the weighted average number of Con Edison common shares outstanding during the period. In the calculation of diluted EPS, weighted average shares outstanding are increased for additional shares that would be outstanding if potentially dilutive securities were converted to common stock. Potentially dilutive securities for Con Edison consist of restricted stock units, deferred stock units and stock options for which the average market price of the common shares for the period was greater than the exercise price. See Note M. Basic and diluted EPS for Con Edison are calculated as follows: For the Years Ended December 31, (Millions of Dollars, except per share amounts/Shares in Millions) 2016 2015 2014 Net income $1,245 $1,193 $1,092 Weighted average common shares outstanding – basic 300.4 293.0 292.9 Add: Incremental shares attributable to effect of potentially dilutive securities 1.5 1.4 1.1 Adjusted weighted average common shares outstanding – diluted 301.9 294.4 294.0 Net Income per common share – basic $4.15 $4.07 $3.73 Net Income per common share – diluted $4.12 $4.05 $3.71 The computation of diluted EPS for the year ended December 31, 2014 excludes immaterial amounts of performance share awards that were not included because of their anti-dilutive effect. Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Changes in Accumulated Other Comprehensive Income/(Loss) by Component Changes to accumulated other comprehensive income/(loss) (OCI) for Con Edison and CECONY are as follows: (Millions of Dollars) Con Edison CECONY Accumulated OCI, net of taxes, at December 31, 2014 (a) $(45) $(11) OCI before reclassifications, net of tax of $(3) for Con Edison 5 1 Amounts reclassified from accumulated OCI related to pension plan liabilities, net of tax of $(4) and $(1) for Con Edison and CECONY, respectively(a)(b) 6 1 Total OCI, net of taxes, at December 31, 2015 11 2 Accumulated OCI, net of taxes, at December 31, 2015 (a) $(34) $(9) OCI before reclassifications, net of tax of $(1) for Con Edison and CECONY 2 1 Amounts reclassified from accumulated OCI related to pension plan liabilities, net of tax of $(3) and $(1) for Con Edison and CECONY, respectively(a)(b) 5 1 Total OCI, net of taxes, at December 31, 2016 7 2 Accumulated OCI, net of taxes, at December 31, 2016 (a) $(27) $(7) (a) Tax reclassified from accumulated OCI is reported in the income tax expense line item of the consolidated income statement. (b) For the portion of unrecognized pension and other postretirement benefit costs relating to the Utilities, costs are recorded into, and amortized out of, regulatory assets instead of OCI. The net actuarial losses and prior service costs recognized during the period are included in the computation of total periodic pension and other postretirement benefit cost. See Notes E and F.

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2016
Regulated Operations [Abstract]
Regulatory Matters	Regulatory Matters Rate Plans The Utilities provide service to New York customers according to the terms of tariffs approved by the NYSPSC. Tariffs for service to customers of Rockland Electric Company (RECO), O&R’s New Jersey regulated utility subsidiary, are approved by the New Jersey Board of Public Utilities (NJBPU). The tariffs include schedules of rates for service that limit the rates charged by the Utilities to amounts that recover from their customers costs approved by the regulator, including capital costs, of providing service to customers as defined by the tariff. The tariffs implement rate plans adopted by state utility regulators in rate orders issued at the conclusion of rate proceedings. Pursuant to the Utilities’ rate plans, there generally can be no change to the charges to customers during the respective terms of the rate plans other than specified adjustments provided for in the rate plans. The Utilities’ rate plans each cover specified periods, but rates determined pursuant to a plan generally continue in effect until a new rate plan is approved by the state utility regulator. Common provisions of the Utilities’ New York rate plans include: Recoverable energy costs that allow the Utilities to recover on a current basis the costs for the energy they supply with no mark-up to their full-service customers. Cost reconciliations that reconcile pension and other postretirement benefit costs, environmental remediation costs, property taxes, variable rate tax-exempt debt and certain other costs to amounts reflected in delivery rates for such costs. Utilities generally retain the right to petition for recovery or accounting deferral of extraordinary and material cost increases and provision is sometimes made for the utility to retain a share of cost reductions, for example, property tax refunds. Revenue decoupling mechanisms that reconcile actual energy delivery revenues to the authorized delivery revenues approved by the NYSPSC. The difference is accrued with interest for refund to, or recovery from customers, as applicable. Earnings sharing that require the Utilities to defer for customer benefit a portion of earnings over specified rates of return on common equity. There is no symmetric mechanism for earnings below specified rates of return on common equity. Negative revenue adjustments for failure to meet certain performance standards relating to service, reliability, safety and other matters. Net utility plant reconciliations that require deferral as a regulatory liability of the revenue requirement impact of the amount, if any, by which actual average net utility plant balances are less than amounts reflected in rates. Rate base is, in general, the sum of the Utilities’ net plant and working capital less deferred taxes. For each rate plan, the NYSPSC uses a forecast of the average rate base for each year that new rates would be in effect (“rate year”). Weighted average cost of capital is determined based on the authorized common equity ratio, return on common equity, cost of long-term debt and customer deposits reflected in each rate plan. For each rate plan, the revenues designed to provide the utility a return on invested capital for each rate year are determined by multiplying each utility rate base by its pre-tax weighted average cost of capital. The Utilities’ actual return on common equity will reflect their actual operations for each rate year, and may be more or less than the authorized return on equity reflected in their rate plans (and if more, may be subject to earnings sharing). The following tables contain a summary of the Utilities’ rate plans: CECONY – Electric Effective period January 2014 – December 2016 January 2017 - December 2019 (b) Base rate changes Yr. 1 – $(76.2) million (a) Yr. 1 - $195 million (b) Amortizations to income of net regulatory (assets) and liabilities Yr. 1 and 2 – $(37) million (c) Yr. 1 - $84 million Other revenue sources Retention of $90 million of annual transmission congestion revenues. Retention of $75 million of annual transmission congestion revenues. Revenue decoupling mechanisms In 2014, 2015 and 2016, the company deferred for customer benefit $146 million, $98 million and $101 million of revenues, respectively. Continuation of reconciliation of actual to authorized electric delivery revenues. Recoverable energy costs (d) Current rate recovery of purchased power and fuel costs. Continuation of current rate recovery of purchased power and fuel costs. Negative revenue adjustments Potential penalties (up to $400 million annually) if certain performance targets are not met. In 2014, the company recorded a $5 million negative revenue adjustment. In 2015 and 2016, the company did not record any negative revenue adjustments. Potential penalties if certain performance targets relating to service, reliability, safety and other matters are not met: Cost reconciliations In 2014, 2015 and 2016, the company deferred $57 million, $26 million and $68 million of net regulatory liabilities, respectively (e). Continuation of reconciliation of expenses for pension and other postretirement benefits, variable-rate tax-exempt debt, major storms, property taxes(e), municipal infrastructure support costs(f), the impact of new laws and environmental site investigation and remediation to amounts reflected in rates.(g) Net utility plant reconciliations Target levels reflected in rates were: Target levels reflected in rates: Average rate base Yr. 1 – $17,323 million Yr. 1 - $18,902 million Weighted average cost of capital (after-tax) Yr. 1 – 7.05 percent Yr. 1 - 6.82 percent Authorized return on common equity Yrs. 1 and 2 – 9.2 percent 9.0 percent Earnings sharing Most earnings above an annual earnings threshold of 9.8 percent for Yrs. 1 and 2 and 9.6 percent for Yr. 3 are to be applied to reduce regulatory assets for environmental remediation and other costs. In 2014 the company had no earnings above the threshold. Actual earnings were $44.4 million and $6.5 million above the threshold for 2015 and 2016, respectively. Most earnings above an annual earnings threshold of 9.5 percent are to be applied to reduce regulatory assets for environmental remediation and other costs accumulated in the rate year. Cost of long-term debt Yr. 1 – 5.17 percent Yr. 1 - 4.93 percent Common equity ratio 48 percent 48 percent (a) The impact of these base rate changes was deferred which resulted in a $30 million regulatory liability at December 31, 2015; this amount has been amortized to $0 at December 31, 2016. (b) In January 2017, the NYSPSC approved the September 2016 Joint Proposal for CECONY's electric rate plan for January 2017 through December 2019. The electric base rate increases are in addition to a $48 million increase resulting from the December 2016 expiration of a temporary credit under the prior rate plan. At the NYSPSC’s option, these increases are being implemented with increases of $199 million in each rate year. Base rates reflect recovery by the company of certain costs of its energy efficiency, system peak reduction and electric vehicle programs (Yr. 1 - $20.5 million ; Yr. 2 - $49 million ; and Yr. 3 - $107.5 million ) over a ten -year period, including the overall pre-tax rate of return on such costs. (c) Amounts reflect annual amortization of $107 million of the regulatory asset for deferred Superstorm Sandy and other major storm costs. The costs recoverable from customers were reduced by $4 million . The costs are no longer subject to NYSPSC staff review and the recovery of the costs is no longer subject to refund. In 2016, an additional $123 million of net regulatory liabilities were amortized to income. (d) For transmission service provided pursuant to the open access transmission tariff of PJM Interconnection LLC (PJM), unless and until changed by the NYSPSC, the company will recover all charges incurred associated with the transmission service. Starting in January 2014, PJM submitted to the FERC a series of requests that substantially increase the charges for the transmission service. CECONY has challenged each of these requests. To date, FERC has rejected all but one of CECONY’s protests. In April 2016, CECONY notified PJM that it will not be exercising its option to continue the service beyond April 2017. CECONY is continuing to challenge FERC’s approval of the increased charges that are being incurred through the end of the current contract term. In June 2015 and May 2016, CECONY filed appeals of certain FERC decisions with the U.S. Court of Appeals. (e) Deferrals for property taxes are limited to 90 percent of the difference from amounts reflected in rates, subject to an annual maximum for the remaining difference of not more than a maximum number of basis points (5.0, 7.5 or 10.0 basis points, depending on the year). (f) In general, if actual expenses for municipal infrastructure support (other than company labor) are below the amounts reflected in rates the company will defer the difference for credit to customers, and if the actual expenses are above the amount reflected in rates the company will defer for recovery from customers 80 percent of the difference subject to a maximum deferral of 30 percent of the amount reflected in rates. (g) In addition, amounts reflected in rates relating to the regulatory asset for future income tax and the excess deferred federal income tax liability are subject to reconciliation. The NYSPSC staff is to audit the regulatory asset and the tax liability. Differences resulting from the NYSPSC staff review will be deferred for NYSPSC determination of any amounts to be refunded or collected from customers. CECONY – Gas Effective period January 2014 – December 2016 January 2017 - December 2019 (b) Base rate changes Yr. 1 – $(54.6) million (a) Yr. 1 - $(5) million (b) Amortizations to income of net regulatory (assets) and liabilities $4 million over three years Yr. 1 - $39 million Other revenue sources Retention of revenues from non-firm customers of up to $65 million and 15 percent of any such revenues above $65 million. The company retained $70 million, $66 million and $65 million of such revenues in 2014, 2015 and 2016, respectively. Retention of annual revenues from non-firm customers of up to $65 million and 15 percent of any such revenues above $65 million. Revenue decoupling mechanisms In 2014, 2015 and 2016, the company deferred $28 million, $54 million and $71 million of regulatory liabilities, respectively. Continuation of reconciliation of actual to authorized gas delivery revenues. Recoverable energy costs Current rate recovery of purchased gas costs. Continuation of current rate recovery of purchased gas costs. Negative revenue adjustments Potential penalties (up to $33 million in 2014, $44 million in 2015, and $56 million in 2016) if certain gas performance targets are not met. In 2014, 2015 and 2016, the company did not record any negative revenue adjustments. Potential penalties if performance targets relating to service, safety and other matters are not met: Cost reconciliations In 2014, 2015 and 2016, the company deferred $38 million, $11 million, and $32 million of net regulatory liabilities, respectively. (c) Continuation of reconciliation of expenses for pension and other postretirement benefits, variable-rate tax-exempt debt, major storms, property taxes, municipal infrastructure support costs, the impact of new laws and environmental site investigation and remediation to amounts reflected in rates.(d) Net utility plant reconciliations Target levels reflected in rates were: Target levels reflected in rates: Average rate base Yr. 1 – $3,521 million Yr. 1 - $4,841 million Weighted average cost of capital Yr. 1 – 7.10 percent Yr. 1 - 6.82 percent Authorized return on common equity 9.3 percent 9.0 percent Earnings sharing Most earnings above an annual earnings threshold of 9.9 percent are to be applied to reduce regulatory assets for environmental remediation and other costs. In 2014, 2015 and 2016, the company had no earnings above the threshold. Most earnings above an annual earnings threshold of 9.5 percent are to be applied to reduce regulatory assets for environmental remediation and other costs accumulated in the rate year. Cost of long-term debt Yr. 1 – 5.17 percent Yr. 1 - 4.93 percent Common equity ratio 48 percent 48 percent (a) The impact of these base rate changes was deferred which resulted in a $32 million regulatory liability at December 31, 2016. (b) In January 2017, the NYSPSC approved the September 2016 Joint Proposal for CECONY's gas rate plan for January 2017 through December 2019. The gas base rate decrease is offset by a $41 million increase resulting from the December 2016 expiration of a temporary credit under the prior rate plan. (c) Deferrals for property taxes are limited to 90 percent of the difference from amounts reflected in rates, subject to an annual maximum for the remaining difference of not more than a 10 basis point impact on return on common equity (d) See footnotes (e), (f) and (g) to the table under "CECONY - Electric" above. CECONY – Steam Effective period January 2014 – December 2016 (a) Base rate changes Yr. 1 – $(22.4) million (b) Amortizations to income of net regulatory (assets) and liabilities $37 million over three years Recoverable energy costs Current rate recovery of purchased power and fuel costs. Negative revenue adjustments Potential penalties (up to $1 million annually) if certain steam performance targets are not met. In 2014, 2015 and 2016, the company did not record any negative revenue adjustments. Cost reconciliations (c) In 2014, 2015 and 2016, the company deferred $42 million of net regulatory liabilities, $17 million of net regulatory assets and $8 million of net regulatory liabilities, respectively. Net utility plant reconciliations Target levels reflected in rates were: Average rate base Yr. 1 – $1,511 million Weighted average cost of capital (after-tax) Yr. 1 – 7.10 percent Authorized return on common equity 9.3 percent Earnings sharing Weather normalized earnings above an annual earnings threshold of 9.9 percent are to be applied to reduce regulatory assets for environmental remediation and other costs. In 2014, the company had no earnings above the threshold. Actual earnings were $11.5 million and $7.8 million above the threshold in 2015 and 2016, respectively. Cost of long-term debt Yr. 1 – 5.17 percent Common equity ratio 48 percent (a) Rates determined pursuant to this rate plan continue in effect until a new rate plan is approved by the NYSPSC. (b) The impact of these base rate changes was deferred which resulted in an $8 million regulatory liability at December 31, 2016. (c) Deferrals for property taxes are limited to 90 percent of the difference from amounts reflected in rates, subject to an annual maximum for the remaining difference of not more than a 10 basis point impact on return on common equity. O&R New York – Electric Effective period July 2012 – June 2015 November 2015 - October 2017 Base rate changes Yr. 1 – $19.4 million Yr. 1 – $9.3 million – $8.8 million Amortizations to income of net regulatory (assets) and liabilities $(32.2) million over three years Yr. 1 – $(8.5) million (a) – $(9.4) million (a) Revenue decoupling mechanisms In 2012, 2013 and 2014, the company deferred for the customer’s benefit $2.6 million, $3.2 million and $(3.4) million, respectively. In 2015 and 2016, the company deferred for the customer’s benefit an immaterial amount and $6.3 million as regulatory liabilities, respectively. Recoverable energy costs Current rate recovery of purchased power and fuel costs. Continuation of current rate recovery of purchased power costs. Negative revenue adjustments Potential penalties (up to $3 million annually) if certain customer service and system reliability performance targets are not met. In 2012, 2013 and 2014, the company did not record any negative revenue adjustments. Potential penalties (up to $4 million annually) if certain performance targets are not met. In 2015 the company recorded $1.25 million in negative revenue adjustments. In 2016, the company did not record any negative revenue adjustments. Cost reconciliations In 2012, 2013 and 2014, the company deferred $7.8 million, $4.1 million and $(0.2) million as a net increase/(decrease) to regulatory assets, respectively. In 2015 and 2016, the company deferred $0.3 million and $7.4 million as net decreases to regulatory assets, respectively. Net utility plant reconciliations Target levels reflected in rates were: Target levels reflected in rates are: – $928 million (b) – $970 million (b) The company increased/(reduced) its regulatory asset by $2.2 million and $(1.9) million in 2015 and 2016, respectively. Average rate base Yr. 1 – $671 million Yr. 1 – $763 million – $805 million Weighted average cost of capital (after-tax) Yr. 1 – 7.61 percent Yr. 1 – 7.10 percent – 7.06 percent Authorized return on common equity Yr. 1 – 9.4 percent 9.0 percent Earnings sharing The company recorded a regulatory liability of $1 million for earnings above the sharing threshold under the rate plan as of December 31, 2014. Most earnings above an annual earnings threshold of 9.6 percent are to be applied to reduce regulatory assets. In 2015, earnings did not exceed the earnings threshold. Actual earnings were $6.1 million above the threshold for 2016. Cost of long-term debt Yr. 1 – 6.07 percent Yr. 1 – 5.42 percent – 5.35 percent Common equity ratio 48 percent 48 percent (a) $59.3 million of the regulatory asset for deferred storm costs is to be recovered from customers over a five year period, including $11.85 million in each of years 1 and 2, $1 million of the regulatory asset for such costs will not be recovered from customers, and all outstanding issues related to Superstorm Sandy and other past major storms prior to November 2014 are resolved. Approximately $4 million of regulatory assets for property tax and interest rate reconciliations will not be recovered from customers. Amounts that will not be recovered from customers were charged-off in June 2015. (b) Excludes electric AMI as to which the company will be required to defer as a regulatory liability the revenue requirement impact of the amount, if any, by which actual average net utility plant balances are less than amounts reflected in rates: $1 million in year 1 and $9 million in year 2. O&R New York – Gas Effective period November 2009 – December 2014 November 2015 – October 2018 Base rate changes Yr. 1 – $9 million Yr. 1 – $16.4 million – $16.4 million – $5.8 million – $10.6 million collected through a surcharge Amortization to income of net regulatory (assets) and liabilities $(2) million over three years Yr. 1 – $(1.7) million (a) – $(2.1) million (a) – $(2.5) million (a) Revenue decoupling mechanisms In 2012, 2013 and 2014, the company deferred $4.7 million, $0.7 million and $(0.1) million of regulatory liabilities, respectively. In 2015 and 2016, the company deferred $0.8 million regulatory assets and $6.2 million of regulatory liabilities, respectively. Recoverable energy costs Current rate recovery of purchased gas costs. Current rate recovery of purchased gas costs. Negative revenue adjustments Potential penalties (up to $1.4 million annually) if certain operations and customer service requirements are not met. In 2012, 2013 and 2014, the company did not record any negative revenue adjustments. Potential penalties (up to $3.7 million in Yr. 1, $4.7 million in Yr. 2 and $5.8 million in Yr. 3) if certain performance targets are not met. In 2015 and 2016, the company did not record any negative revenue adjustments. Cost reconciliations In 2012, 2013 and 2014, the company deferred $0.7 million, $8.3 million and $8.3 million as net regulatory assets, respectively. In 2015 and 2016, the company deferred $4.5 million and $6.6 million as net regulatory liabilities and assets, respectively. Net utility plant reconciliations The company deferred $0.7 million in 2012 as a regulatory asset and no deferrals were recorded for 2013 or 2014. Target levels reflected in rates are: – $492 million (b) – $518 million (b) – $546 million (b) No deferral was recorded for 2015 and an immaterial amount was recorded as a regulatory liability in 2016. Average rate base Yr. 1 – $280 million Yr. 1 – $366 million – $391 million – $417 million Weighted average cost of capital (after-tax) 8.49 percent Yr. 1 – 7.10 percent – 7.06 percent – 7.06 percent Authorized return on common equity 10.4 percent 9.0 percent Earnings sharing Earnings above an annual earnings threshold of 11.4 percent are to be applied to reduce regulatory assets. In 2012, 2013 and 2014, earnings did not exceed the earnings threshold. Most earnings above an annual earnings threshold of 9.6 percent are to be applied to reduce regulatory assets. In 2015, earnings did not exceed the earnings threshold. Actual earnings were $4 million above the threshold for 2016. Cost of long-term debt 6.81 percent Yr. 1 – 5.42 percent – 5.35 percent – 5.35 percent Common equity ratio 48 percent 48 percent (a) Reflects that the company will not recover from customers a total of approximately $14 million of regulatory assets for property tax and interest rate reconciliations. Amounts that will not be recovered from customers were charged-off in June 2015. (b) Excludes gas AMI as to which the company will be required to defer as a regulatory liability the revenue requirement impact of the amount, if any, by which actual average net utility plant balances are less than amounts reflected in rates: $0.5 million in year 1, $4.2 million in year 2 and $7.2 million in year 3. RECO Effective period May 2010 – July 2014 August 2014 – July 2015 (a) Base rate changes Yr. 1 – $9.8 million Yr. 1 – $13.0 million Amortization to income of net regulatory (assets) and liabilities $(3.9) million over four years and $(4.9) million of deferred storm costs over five years $0.4 million over three years and $(25.6) million of deferred storm costs over four years Recoverable energy costs Current rate recovery of purchased power costs. Current rate recovery of purchased power costs. Cost reconciliations None None Average rate base $148.6 million $172.2 million Weighted average cost of capital (after-tax) 8.21 percent 7.83 percent Authorized return on common equity 10.3 percent 9.75 percent Cost of long-term debt 6.16 percent 5.89 percent Common equity ratio 50 percent 50 percent (a) In January 2016, the NJBPU approved RECO’s plan for a 3 -year, $15.7 million electric system storm hardening capital program, the costs of which RECO, beginning in 2017, is collecting through a customer surcharge until a new rate plan is approved that reflects the costs. In February 2017, RECO, the staff of the NJBPU and other parties entered into a stipulation of settlement for a RECO electric rate plan for the period commencing March 2017. The stipulation is subject to NJBPU approval. The rate plan would provide for an electric rate increase of $1.7 million , reflecting a return on common equity of 9.6 percent and a common equity ratio of 49.7 percent , and for continuation of the provisions for recovery from customers of the cost of purchased power. In January 2017, RECO filed a request with FERC for an increase to its annual transmission revenue requirement from $11.8 million to $19.7 million , effective April 2017. The filing reflects a return on common equity of 10.7 percent and a common equity ratio of 48 percent . Other Regulatory Matters In June 2014, the NYSPSC initiated a proceeding to investigate the practices of qualifying persons to perform plastic fusions on gas facilities. New York State regulations require gas utilities to qualify and, except in certain circumstances, annually requalify workers that perform fusion to join plastic pipe. The NYSPSC directed the New York gas utilities to provide information in this proceeding about their compliance with the qualification and requalification requirements and related matters; their procedures for compliance with all gas safety regulations; and their annual chief executive officer certifications regarding these and other procedures. CECONY’s qualification and requalification procedures had not included certain required testing to evaluate specimen fuses. In addition, CECONY and O&R had not timely requalified certain workers that had been qualified under their respective procedures to perform fusion to join plastic pipe. CECONY and O&R have requalified their workers who perform plastic pipe fusions. In May 2015, the NYSPSC, which indicated that it would address enforcement at a later date, ordered CECONY, O&R and other gas utilities to perform risk assessment and remediation plans, additional leakage surveying and reporting; CECONY to hire an independent statistician to develop a risk assessment and remediation plan; and the gas utilities to implement certain new plastic fusion requirements. In December 2015, the NYSPSC staff informed O&R that the company had satisfactorily completed its risk assessment and remediation plan. CECONY is implementing the three -year risk assessment and remediation plan it submitted to the NYSPSC staff in October 2016. In November 2015, the NYSPSC ordered CECONY to show cause why the NYSPSC should not commence proceedings to penalize the company for alleged violations of gas safety regulations identified by the NYSPSC staff in its investigation of a March 2014 explosion and fire and to review the prudence of the company's conduct associated with the incident. See "Manhattan Explosion and Fire" in Note H. In December 2015, the company responded that the NYSPSC should not institute the proceedings and disputed the alleged violations. In February 2017, the NYSPSC approved a settlement agreement with CECONY related to the June 2014 plastic fusion proceeding and the November 2015 order to show cause. Pursuant to the settlement agreement, the company will not recover from customers $126 million of costs it incurred for gas emergency response activities in 2014, 2015 and 2016 in excess of amounts reflected in its gas rate plan for those years. At December 31, 2016, the company had not deferred any such incremental costs as a regulatory asset. In addition, the company will provide $27 million of future benefits to customers. At December 31, 2016, the Company had accrued a regulatory liability for these future benefits. Regulatory Assets and Liabilities Regulatory assets and liabilities at December 31, 2016 and 2015 were comprised of the following items: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Regulatory assets Unrecognized pension and other postretirement costs $2,874 $3,876 $2,730 $3,697 Future income tax 2,439 2,350 2,325 2,232 Environmental remediation costs 823 904 711 800 Revenue taxes 295 253 280 240 Deferred storm costs 56 185 3 110 Deferred derivative losses 48 50 42 46 Unamortized loss on reacquired debt 43 50 41 48 Recoverable energy costs 42 16 38 15 Pension and other postretirement benefits deferrals 38 45 7 16 O&R property tax reconciliation 37 46 — — Surcharge for New York State assessment 28 44 26 40 Preferred stock redemption 25 26 25 26 Net electric deferrals 24 44 24 44 O&R transition bond charges 15 21 — — Workers’ compensation 13 11 13 11 Other 224 175 208 157 Regulatory assets – noncurrent 7,024 8,096 6,473 7,482 Deferred derivative losses 91 113 86 103 Recoverable energy costs 9 19 4 18 Regulatory assets – current 100 132 90 121 Total Regulatory Assets $7,124 $8,228 $6,563 $7,603 Regulatory liabilities Allowance for cost of removal less salvage $755 $676 $641 $570 Pension and other postretirement benefit deferrals 193 76 162 46 Property tax reconciliation 178 303 178 303 Net unbilled revenue deferrals 145 109 145 109 Prudence proceeding 95 99 95 99 Carrying charges on repair allowance and bonus depreciation 68 49 67 48 New York State income tax rate change 61 75 60 72 Unrecognized other postretirement costs 60 28 60 28 Variable-rate tax-exempt debt - cost rate reconciliation 55 70 48 60 Base rate change deferrals 40 128 40 128 Earnings sharing - electric, gas and steam 39 80 28 80 Net utility plant reconciliations 16 32 15 31 Property tax refunds 1 44 1 44 World Trade Center settlement proceeds — 21 — 21 Other 199 187 172 150 Regulatory liabilities – noncurrent 1,905 1,977 1,712 1,789 Revenue decoupling mechanism 71 45 61 45 Refundable energy costs 29 64 5 33 Deferred derivative gains 28 6 24 6 Regulatory liabilities—current 128 115 90 84 Total Regulatory Liabilities $2,033 $2,092 $1,802 $1,873 Prudence proceeding represents the remaining amount to be credited to customers pursuant to a Joint Proposal, approved by the NYSPSC in April 2016, with respect to the prudence of certain CECONY expenditures and related matters. Unrecognized pension and other postretirement costs represent the net regulatory asset associated with the accounting rules for retirement benefits. See Note A. Deferred storm costs represent response and restoration costs, other than capital expenditures, in connection with Superstorm Sandy and other major storms that were deferred by the Utilities. Net electric deferrals represent the remaining unamortized balance of certain regulatory assets and liabilities of CECONY that were combined effective April 1, 2010 and are being amortized to income through March 31, 2018. Revenue taxes represent the timing difference between taxes collected and paid by the Utilities to fund mass transportation. The NYSPSC has authorized CECONY to accrue unbilled electric, gas and steam revenues. CECONY has deferred the net margin on the unbilled revenues for the future benefit of customers by recording a regulatory liability of $145 million and $109 million at December 31, 2016 and 2015 , respectively, for the difference between the unbilled revenues and energy cost liabilities. Electricity Purchase Agreements The Utilities have electricity purchase agreements with non-utility generators and others for generating capacity. The Utilities recover their purchased power costs in accordance with provisions approved by the applicable state public utility regulators. See “Recoverable Energy Costs” in Note A. At December 31, 2016 , the significant terms of the electricity purchase agreements with non-utility generators were as follows: Facility Equity Owner Plant Output (MW) Contracted Output (MW) Contract Start Date Contract Term (Years) Brooklyn Navy Yard Brooklyn Navy Yard Cogeneration Partners, LP 322 293 November 1996 40 Linden Cogeneration Cogen Technologies Linden Venture, LP 974 630 May 1992 25 Indian Point Entergy Nuclear Power Marketing, LLC 2,150 500 August 2001 16 The Utilities also conducted auctions and have entered into various other electricity purchase agreements. Assuming performance by the parties to the electricity purchase agreements, the Utilities are obligated over the terms of the agreements to make capacity and other fixed payments. The future capacity and other fixed payments under the contracts are estimated to be as follows: (Millions of Dollars) 2017 2018 2019 2020 2021 All Years Thereafter Con Edison $178 $125 $120 $76 $54 $710 CECONY 178 125 119 75 54 710 For energy delivered under most of the electricity purchase agreements, CECONY is obligated to pay variable prices. The company’s payments under the agreements for capacity, energy and other fixed payments in 2016 , 2015 and 2014 were as follows: For the Years Ended December 31, (Millions of Dollars) 2016 2015 2014 Linden Cogeneration $304 $323 $381 Indian Point 203 226 247 Astoria Energy (a) 50 178 230 Astoria Generating Company 16 — — Brooklyn Navy Yard 119 113 133 Indeck Corinth (b) — 25 80 Selkirk (c) — — 144 Independence (c) — — 97 Total $692 $865 $1,312 (a) Contract term ended in 2016. (b) Contract term ended in 2015. (c) Contract term ended in 2014

Capitalization

Capitalization	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Capitalization	Capitalization Common Stock At December 31, 2016 and 2015 , Con Edison owned all of the issued and outstanding shares of common stock of the Utilities, the Clean Energy Businesses and Con Edison Transmission. CECONY owns 21,976,200 shares of Con Edison stock, which it purchased prior to 2001 in connection with Con Edison’s stock repurchase plan. CECONY presents in the financial statements the cost of the Con Edison stock it owns as a reduction of common shareholder’s equity. Capitalization of Con Edison The outstanding capitalization for each of the Companies is shown on its Consolidated Statement of Capitalization, and for Con Edison includes outstanding debt of the Utilities and the Clean Energy Businesses. Dividends In accordance with NYSPSC requirements, the dividends that the Utilities generally pay are limited to not more than 100 percent of their respective income available for dividends calculated on a two -year rolling average basis. Excluded from the calculation of “income available for dividends” are non-cash charges to income resulting from accounting changes or charges to income resulting from significant unanticipated events. The restriction also does not apply to dividends paid in order to transfer to Con Edison proceeds from major transactions, such as asset sales, or to dividends reducing each utility subsidiary’s equity ratio to a level appropriate to its business risk. Long-term Debt Long-term debt maturing in the period 2017 - 2021 is as follows: (Millions of Dollars) Con Edison CECONY 2017 $39 $— 2018 1,688 1,200 2019 574 475 2020 388 350 2021 540 — CECONY has issued $450 million of tax-exempt debt through the New York State Energy Research and Development Authority (NYSERDA) that currently bear interest at a rate determined weekly and is subject to tender by bondholders for purchase by the company. The carrying amounts and fair values of long-term debt at December 31, 2016 and 2015 are: (Millions of Dollars) 2016 2015 Long-Term Debt (including current portion) Carrying Amount Fair Value Carrying Amount Fair Value Con Edison $14,774 $16,093 $12,745 $13,856 CECONY $12,073 $13,268 $11,437 $12,427 Fair values of long-term debt have been estimated primarily using available market information. For Con Edison, $15,457 million and $636 million of the fair value of long-term debt at December 31, 2016 are classified as Level 2 and Level 3, respectively. For CECONY, $12,632 million and $636 million of the fair value of long-term debt at December 31, 2016 are classified as Level 2 and Level 3, respectively (see Note P). The $636 million of long-term debt classified as Level 3 is CECONY’s tax-exempt, auction-rate securities for which the market is highly illiquid and there is a lack of observable inputs. At December 31, 2016 and 2015, long-term debt of Con Edison included $845 million and $339 million , respectively, of non-recourse debt secured by the pledge of the applicable renewable energy production projects of the Clean Energy Businesses. At December 31, 2016 and 2015 , long-term debt of Con Edison included $11 million and $15 million , respectively, of Transition Bonds issued in 2004 by O&R’s New Jersey utility subsidiary through a special purpose entity. Significant Debt Covenants The significant debt covenants under the financing arrangements for the Companies' debentures and Con Edison's notes and term loan include obligations to pay principal and interest when due and covenants not to consolidate with or merge into any other corporation unless certain conditions are met. In addition, the notes include a covenant that the company shall continue its utility business in New York City, the term loan includes a covenant that, subject to certain exceptions, the company and its subsidiaries will not mortgage, lien, pledge or otherwise encumber its assets, and the notes and term loan provide that the company shall not permit its ratio of consolidated debt to consolidated capital to exceed certain amounts ( 0.675 to 1 for the notes and 0.65 to 1 for the term loan) and include cross default provisions with respect to other indebtedness of the company or its subsidiaries (material subsidiaries, in the case of the notes) having a then outstanding principal balance in excess of certain amounts ( $100 million for the notes and $150 million for the term loan). The Companies' debentures have no cross default provisions. The tax-exempt financing arrangements of CECONY are subject to covenants for the debentures discussed above and the covenants discussed below. The Companies were in compliance with their significant debt covenants at December 31, 2016 . The tax-exempt financing arrangements involved the issuance of uncollateralized promissory notes of CECONY to NYSERDA in exchange for the net proceeds of a like amount of tax-exempt bonds with substantially the same terms sold to the public by NYSERDA. The tax-exempt financing arrangements include covenants with respect to the tax-exempt status of the financing, including covenants with respect to the use of the facilities financed. The arrangements include provisions for the maintenance of liquidity and credit facilities, the failure to comply with which would, except as otherwise provided, constitute an event of default for the debt to which such provisions applied. The failure to comply with debt covenants would, except as otherwise provided, constitute an event of default for the debt to which such provisions applied. If an event of default were to occur, the principal and accrued interest on the debt to which such event of default applied and, in the case of the Con Edison notes, a make-whole premium might and, in the case of certain events of default would, become due and payable immediately. The liquidity and credit facilities currently in effect for the tax-exempt financing include covenants that the ratio of debt to total capital of CECONY will not at any time exceed 0.65 to 1 and that, subject to certain exceptions, CECONY will not mortgage, lien, pledge or otherwise encumber its assets. Certain of the facilities also include as events of default, defaults in payments of other debt obligations in excess of specified levels ( $150 million or $100 million , depending on the facility).

Short-Term Borrowing

Short-Term Borrowing	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Short-Term Borrowing	Short-Term Borrowing In December 2016, Con Edison and the Utilities entered into a credit agreement (Credit Agreement), under which banks are committed to provide loans and letters of credit on a revolving credit basis. The Credit Agreement expires in December 2021. There is a maximum of $2,250 million of credit available. The full amount is available to CECONY and $1,000 million (subject to increase up to $1,500 million ) is available to Con Edison, including up to $1,200 million of letters of credit. The Credit Agreement supports the Companies’ commercial paper programs. The Companies have not borrowed under the Credit Agreement. At December 31, 2016 , Con Edison had $1,054 million of commercial paper outstanding, of which $600 million was outstanding under CECONY’s program. The weighted average interest rate at December 31, 2016 was 1.0 percent for both Con Edison and CECONY. At December 31, 2015 , Con Edison had $1,529 million of commercial paper outstanding of which $1,033 million was outstanding under CECONY’s program. The weighted average interest rate at December 31, 2015 was 0.7 percent for both Con Edison and CECONY. At December 31, 2016 and 2015 , no loans were outstanding under the Credit Agreement and $2 million (including $2 million for CECONY) and $15 million of letters of credit were outstanding under the Credit Agreement, respectively. The banks’ commitments under the Credit Agreement are subject to certain conditions, including that there be no event of default. The commitments are not subject to maintenance of credit rating levels or the absence of a material adverse change. Upon a change of control of, or upon an event of default by one of the Companies, the banks may terminate their commitments with respect to that company, declare any amounts owed by that company under the Credit Agreement immediately due and payable and require that company to provide cash collateral relating to the letters of credit issued for it under the Credit Agreement. Events of default include the exceeding at any time of a ratio of consolidated debt to consolidated total capital of 0.65 to 1 (at December 31, 2016 this ratio was 0.51 to 1 for Con Edison and 0.52 to 1 for CECONY); having liens on its assets in an aggregate amount exceeding five percent of its consolidated total capital, subject to certain exceptions; and the failure, following any applicable notice period, to meet certain other customary covenants. Interest and fees charged for the revolving credit facilities and any loans made or letters of credit issued under the Credit Agreement reflect the Companies’ respective credit ratings. The Companies were in compliance with their covenants at December 31, 2016 . See Note S for information about short-term borrowing between related parties.

Pension Benefits

Pension Benefits	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Pension Benefits	Pension Benefits Con Edison maintains a tax-qualified, non-contributory pension plan that covers substantially all employees of CECONY and O&R and certain employees of the Clean Energy Businesses. The plan is designed to comply with the Internal Revenue Code and the Employee Retirement Income Security Act of 1974. In addition, Con Edison maintains additional non-qualified supplemental pension plans. Total Periodic Benefit Cost The components of the Companies’ total periodic benefit costs for 2016 , 2015 and 2014 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 Service cost – including administrative expenses $275 $297 $227 $258 $279 $211 Interest cost on projected benefit obligation 596 575 572 559 538 536 Expected return on plan assets (947) (886) (832) (898) (840) (789) Recognition of net actuarial loss 596 775 618 565 734 586 Recognition of prior service costs 4 4 4 2 2 2 NET PERIODIC BENEFIT COST $524 $765 $589 $486 $713 $546 Amortization of regulatory asset (a) — 1 2 — 1 2 TOTAL PERIODIC BENEFIT COST $524 $766 $591 $486 $714 $548 Cost capitalized (214) (301) (225) (203) (285) (212) Reconciliation to rate level 54 (74) 118 58 (74) 108 Cost charged to operating expenses $364 $391 $484 $341 $355 $444 (a) Relates to an increase in CECONY’s pension obligation of $45 million from a 1999 special retirement program. Funded Status The funded status at December 31, 2016 , 2015 and 2014 was as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 CHANGE IN PROJECTED BENEFIT OBLIGATION Projected benefit obligation at beginning of year $14,377 $15,081 $12,197 $13,482 $14,137 $11,429 Service cost – excluding administrative expenses 271 293 221 254 274 206 Interest cost on projected benefit obligation 596 575 572 559 538 536 Net actuarial (gain)/loss (302) (996) 2,641 (282) (931) 2,484 Plan amendments (256) — 6 (259) — — Benefits paid (591) (576) (556) (551) (536) (518) PROJECTED BENEFIT OBLIGATION AT END OF YEAR $14,095 $14,377 $15,081 $13,203 $13,482 $14,137 CHANGE IN PLAN ASSETS Fair value of plan assets at beginning of year $11,759 $11,495 $10,755 $11,141 $10,897 $10,197 Actual return on plan assets 829 126 752 787 118 715 Employer contributions 508 750 578 469 697 535 Benefits paid (591) (576) (556) (551) (536) (518) Administrative expenses (33) (36) (34) (31) (35) (32) FAIR VALUE OF PLAN ASSETS AT END OF YEAR $12,472 $11,759 $11,495 $11,815 $11,141 $10,897 FUNDED STATUS $(1,623) $(2,618) $(3,586) $(1,388) $(2,341) $(3,240) Unrecognized net loss $3,157 $3,909 $4,888 $2,995 $3,704 $4,616 Unrecognized prior service costs (244) 16 20 (258) 3 4 Accumulated benefit obligation 12,655 12,909 13,454 11,806 12,055 12,553 The decrease in the pension plan’s projected benefit obligation was the primary cause of the decreased pension liability at Con Edison and CECONY of $995 million and $953 million , respectively, compared with December 31, 2015 . For Con Edison, this decrease in pension liability corresponds with a decrease to regulatory assets of $1,002 million for unrecognized net losses and unrecognized prior service costs associated with the Utilities consistent with the accounting rules for regulated operations, a credit to OCI of $5 million (net of taxes) for the unrecognized net losses, and an immaterial change to OCI (net of taxes) for the unrecognized prior service costs associated with the Clean Energy Businesses and RECO. For CECONY, the decrease in pension liability corresponds with a decrease to regulatory assets of $967 million for unrecognized net losses and unrecognized prior service costs consistent with the accounting rules for regulated operations, a credit to OCI of $1 million (net of taxes) for unrecognized net losses, and an immaterial change to OCI (net of taxes) for the unrecognized prior service costs associated with the Clean Energy Businesses. A portion of the unrecognized net loss and prior service cost for the pension plan, equal to $579 million and $(16) million , respectively, will be recognized from accumulated OCI and the regulatory asset into net periodic benefit cost over the next year for Con Edison. Included in these amounts are $548 million and $(18) million , respectively, for CECONY. At December 31, 2016 and 2015 , Con Edison’s investments include $273 million and $243 million , respectively, held in external trust accounts for benefit payments pursuant to the supplemental retirement plans. Included in these amounts for CECONY were $246 million and $221 million , respectively. See Note P. The accumulated benefit obligations for the supplemental retirement plans for Con Edison and CECONY were $303 million and $268 million as of December 31, 2016 and $285 million and $249 million as of December 31, 2015 , respectively. Assumptions The actuarial assumptions were as follows: 2016 2015 2014 Weighted-average assumptions used to determine benefit obligations at December 31: Discount rate 4.25 % 4.25 % 3.90 % Rate of compensation increase CECONY 4.25 % 4.25 % 4.25 % O&R 4.00 % 4.00 % 4.00 % Weighted-average assumptions used to determine net periodic benefit cost for the years ended December 31: Discount rate 4.25 % 3.90 % 4.80 % Expected return on plan assets 7.80 % 7.80 % 8.00 % Rate of compensation increase CECONY 4.25 % 4.25 % 4.35 % O&R 4.00 % 4.00 % 4.25 % The expected return assumption reflects anticipated returns on the plan’s current and future assets. The Companies’ expected return was based on an evaluation of the current environment, market and economic outlook, relationships between the economy and asset class performance patterns, and recent and long-term trends in asset class performance. The projections were based on the plan’s target asset allocation. Discount Rate Assumption To determine the assumed discount rate, the Companies use a model that produces a yield curve based on yields on selected highly rated (Aa or higher by either Moody’s Investors Service (Moody’s) or Standard & Poor’s) corporate bonds. Bonds with insufficient liquidity, bonds with questionable pricing information and bonds that are not representative of the overall market are excluded from consideration. For example, the bonds used in the model cannot be callable, they must have a price between 50 percent and 200 percent of the original price, the yield must lie between 1 percent and 20 percent , and the amount of the bond issue outstanding must be in excess of $50 million . The spot rates defined by the yield curve and the plan’s projected benefit payments are used to develop a weighted average discount rate. Expected Benefit Payments Based on current assumptions, the Companies expect to make the following benefit payments over the next ten years : (Millions of Dollars) 2017 2018 2019 2020 2021 2022-2026 Con Edison $702 $719 $730 $745 $758 $3,990 CECONY 653 670 679 693 705 3,716 Expected Contributions Based on estimates as of December 31, 2016 , the Companies expect to make contributions to the pension plans during 2017 of $423 million (of which $388 million is to be contributed by CECONY). The Companies’ policy is to fund the total periodic benefit cost of the qualified plan to the extent tax deductible and to also contribute to the non-qualified supplemental plans. Plan Assets The asset allocations for the pension plan at the end of 2016 , 2015 and 2014 , and the target allocation for 2017 are as follows: Target Allocation Range Plan Assets at December 31, Asset Category 2017 2016 2015 2014 Equity Securities 52% - 64% 58 % 57 % 58 % Debt Securities 28% - 38% 33 % 33 % 32 % Real Estate 7% - 11% 9 % 10 % 10 % Total 100% 100 % 100 % 100 % Con Edison has established a pension trust for the investment of assets to be used for the exclusive purpose of providing retirement benefits to participants and beneficiaries and payment of plan expenses. Pursuant to resolutions adopted by Con Edison’s Board of Directors, the Management Development and Compensation Committee of the Board of Directors (the Committee) has general oversight responsibility for Con Edison’s pension and other employee benefit plans. The pension plan’s named fiduciaries have been granted the authority to control and manage the operation and administration of the plans, including overall responsibility for the investment of assets in the trust and the power to appoint and terminate investment managers. The investment objectives of the Con Edison pension plan are to maintain a level and form of assets adequate to meet benefit obligations to participants, to achieve the expected long-term total return on the trust assets within a prudent level of risk and maintain a level of volatility that is not expected to have a material impact on the company’s expected contribution and expense or the company’s ability to meet plan obligations. The assets of the plan have no significant concentration of risk in one country (other than the United States), industry or entity. The strategic asset allocation is intended to meet the objectives of the pension plan by diversifying its funds across asset classes, investment styles and fund managers. An asset/liability study typically is conducted every few years to determine whether the current strategic asset allocation continues to represent the appropriate balance of expected risk and reward for the plan to meet expected liabilities. Each study considers the investment risk of the asset allocation and determines the optimal asset allocation for the plan. The target asset allocation for 2017 reflects the results of such a study conducted in 2016. Individual fund managers operate under written guidelines provided by Con Edison, which cover such areas as investment objectives, performance measurement, permissible investments, investment restrictions, trading and execution, and communication and reporting requirements. Con Edison management regularly monitors, and the named fiduciaries review and report to the Committee regarding, asset class performance, total fund performance, and compliance with asset allocation guidelines. Management changes fund managers and rebalances the portfolio as appropriate. At the direction of the named fiduciaries, such changes are reported to the Committee. In May 2015, the FASB issued ASU 2015-07, Fair Value Measurements (Topic 820):Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or its equivalent), which exempts investments measured using net asset value (NAV) practical expedient in ASC 820, Fair Value Measurement, from categorization within the fair value hierarchy. The guidance requires retrospective application and is effective for public business entities for fiscal years, and interim periods within those years, beginning after December 15, 2015. Accordingly, the amendment was retrospectively applied, resulting in the reclassification of real estate funds, private equity and hedge fund investments from Level III assets on the fair value hierarchy to investments measured at net asset value. Assets measured at fair value on a recurring basis are summarized below as defined by the accounting rules for fair value measurements (see Note P). The fair values of the pension plan assets at December 31, 2016 by asset category are as follows: (Millions of Dollars) Level 1 Level 2 Total Investments within the fair value hierarchy U.S. Equity (a) $3,466 $— $3,466 International Equity (b) 3,187 371 3,558 U.S. Government Issued Debt (c) — 1,337 1,337 Corporate Bonds Debt (d) — 2,140 2,140 Structured Assets Debt (e) — 1 1 Other Fixed Income Debt (f) — 200 200 Cash and Cash Equivalents (g) 147 389 536 Futures (h) 296 68 364 Total investments within the fair value hierarchy $7,096 $4,506 $11,602 Investments measured at NAV per share (n) Private Equity (i) 247 Real Estate (j) 1,139 Hedge Funds (k) 229 Total investments valued using NAV per share $1,615 Funds for retiree health benefits (l) (165) (105) (270) Funds for retiree health benefits measured at NAV per share (l)(n) (37) Total funds for retiree health benefits $(307) Investments (excluding funds for retiree health benefits) $6,931 $4,401 $12,910 Pending activities (m) (438) Total fair value of plan net assets $12,472 (a) U.S. Equity includes both actively- and passively-managed assets with investments in domestic equity index funds and actively-managed small-capitalization equities. (b) International Equity includes international equity index funds and actively-managed international equities. (c) U.S. Government Issued Debt includes agency and treasury securities. (d) Corporate Bonds Debt consists of debt issued by various corporations. (e) Structured Assets Debt includes commercial-mortgage-backed securities and collateralized mortgage obligations. (f) Other Fixed Income Debt includes municipal bonds, sovereign debt and regional governments. (g) Cash and Cash Equivalents include short term investments, money markets, foreign currency and cash collateral. (h) Futures consist of exchange-traded financial contracts encompassing U.S. Equity, International Equity and U.S. Government indices. (i) Private Equity consists of global equity funds that are not exchange-traded. (j) Real Estate investments include real estate funds based on appraised values that are broadly diversified by geography and property type. (k) Hedge Funds are within a commingled structure which invests in various hedge fund managers who can invest in all financial instruments. (l) The Companies set aside funds for retiree health benefits through a separate account within the pension trust, as permitted under Section 401(h) of the Internal Revenue Code of 1986, as amended. In accordance with the Code, the plan’s investments in the 401(h) account may not be used for, or diverted to, any purpose other than providing health benefits for retirees. The net assets held in the 401(h) account are calculated based on a pro-rata percentage allocation of the net assets in the pension plan. The related obligations for health benefits are not included in the pension plan’s obligations and are included in the Companies’ other postretirement benefit obligation. See Note F. (m) Pending activities include security purchases and sales that have not settled, interest and dividends that have not been received and reflects adjustments for available estimates at year end. (n) In accordance with ASU 2015-07, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair values of the pension plan assets at December 31, 2015 by asset category are as follows: (Millions of Dollars) Level 1 Level 2 Total Investments within the fair value hierarchy U.S. Equity (a) $3,106 $— $3,106 International Equity (b) 2,874 346 3,220 U.S. Government Issued Debt (c) — 2,222 2,222 Corporate Bonds Debt (d) — 1,356 1,356 Structured Assets Debt (e) — 1 1 Other Fixed Income Debt (f) — 170 170 Cash and Cash Equivalents (g) 115 414 529 Futures (h) 161 132 293 Total investments within the fair value hierarchy $6,256 $4,641 $10,897 Investments measured at NAV per share (n) Private Equity (i) 170 Real Estate (j) 1,248 Hedge Funds (k) 233 Total investments valued using NAV per share $1,651 Funds for retiree health benefits (l) (162) (120) (282) Funds for retiree health benefits measured at NAV per share (l)(n) (43) Total funds for retiree health benefits $(325) Investments (excluding funds for retiree health benefits) $6,094 $4,521 $12,223 Pending activities (m) (464) Total fair value of plan net assets $11,759 (a) - (n) Reference is made to footnotes (a) through (n) in the above table of pension plan assets at December 31, 2016 by asset category. The Companies also offer a defined contribution savings plan that covers substantially all employees and made contributions to the plan as follows: For the Years Ended December 31, (Millions of Dollars) 2016 2015 2014 Con Edison $36 $34 $32 CECONY 32 29 27 Mortality Table Revision The Companies adopted revised mortality tables effective December 31, 2014 in the measurement of its pension and other postretirement benefit plan obligations, accounting costs and required contribution amounts. The revised tables reflect the RP-2014 mortality tables published by the Society of Actuaries in October 2014, as adjusted based on the actual experience of the Companies. The new tables incorporate substantial life expectancy improvements relative to the last tables published in 2000 (RP-2000). As a result of the adoption, Con Edison recognized an increase in its pension benefit obligation of approximately $800 million as of December 31, 2014 . The Companies, under their current New York rate plans, defer as a regulatory asset or liability, as the case may be, the differences between the actual level of expenses for pension and other postretirement benefits and amounts for those expenses reflected in rates.

Other Postretirement Benefits

Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Other Postretirement Benefits	Other Postretirement Benefits The Utilities currently have contributory comprehensive hospital, medical and prescription drug programs for eligible retirees, their dependents and surviving spouses. CECONY also has a contributory life insurance program for bargaining unit employees and provides basic life insurance benefits up to a specified maximum at no cost to certain retired management employees. O&R has a non-contributory life insurance program for retirees. Certain employees of the Clean Energy Businesses are eligible to receive benefits under these programs. Total Periodic Benefit Cost The components of the Companies’ total periodic postretirement benefit costs for 2016 , 2015 and 2014 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 Service cost $18 $20 $19 $13 $15 $15 Interest cost on accumulated other postretirement benefit obligation 48 51 60 40 43 52 Expected return on plan assets (77) (78) (77) (67) (68) (68) Recognition of net actuarial loss 5 31 57 3 28 51 Recognition of prior service cost (20) (20) (19) (14) (14) (15) TOTAL PERIODIC POSTRETIREMENT BENEFIT COST $(26) $4 $40 $(25) $4 $35 Cost capitalized 11 (2) (15) 10 (2) (14) Reconciliation to rate level 22 14 10 22 6 2 Cost charged to operating expenses $7 $16 $35 $7 $8 $23 Funded Status The funded status of the programs at December 31, 2016 , 2015 and 2014 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 CHANGE IN BENEFIT OBLIGATION Benefit obligation at beginning of year $1,287 $1,411 $1,395 $1,093 $1,203 $1,198 Service cost 18 20 19 13 15 15 Interest cost on accumulated postretirement benefit obligation 48 51 60 40 43 52 Amendments — — (12) — — — Net actuarial loss/(gain) (57) (103) 47 (52) (85) 28 Benefits paid and administrative expenses (134) (127) (134) (122) (117) (125) Participant contributions 36 35 36 35 34 35 BENEFIT OBLIGATION AT END OF YEAR $1,198 $1,287 $1,411 $1,007 $1,093 $1,203 CHANGE IN PLAN ASSETS Fair value of plan assets at beginning of year $994 $1,084 $1,113 $870 $950 $977 Actual return on plan assets 60 (6) 59 52 (4) 54 Employer contributions 7 6 7 7 6 7 EGWP payments 35 28 12 33 26 11 Participant contributions 36 35 36 35 34 35 Benefits paid (157) (153) (143) (146) (142) (134) FAIR VALUE OF PLAN ASSETS AT END OF YEAR $975 $994 $1,084 $851 $870 $950 FUNDED STATUS $(223) $(293) $(327) $(156) $(223) $(253) Unrecognized net loss/(gain) $(24) $28 $78 $(42) $4 $45 Unrecognized prior service costs (31) (51) (71) (18) (32) (46) The decrease in the other postretirement benefit plan obligation was the primary cause of the decreased liability for other postretirement benefits at Con Edison and CECONY of $70 million and $67 million , respectively, compared with December 31, 2015 . For Con Edison, this decreased liability corresponds with an increase to regulatory liabilities of $32 million for unrecognized net losses and unrecognized prior service costs associated with the Utilities consistent with the accounting rules for regulated operations, a credit to OCI of $2 million (net of taxes) for the unrecognized net losses and a debit to OCI of $1 million (net of taxes) for the unrecognized prior service costs associated with the Clean Energy Businesses and RECO. For CECONY, the decrease in liability corresponds with an increase to regulatory liabilities of $32 million for unrecognized net losses and unrecognized prior service costs associated with the company consistent with the accounting rules for regulated operations, and a credit to OCI of $1 million (net of taxes) for the unrecognized net losses and an immaterial change to OCI (net of taxes) for the unrecognized prior service costs associated with the Clean Energy Businesses. A portion of the unrecognized net losses and prior service costs for the other postretirement benefits, equal to $4 million and $(17) million , respectively, will be recognized from accumulated OCI and the regulatory asset into net periodic benefit cost over the next year for Con Edison. Included in these amounts are $1 million and $(11) million , respectively, for CECONY. Assumptions The actuarial assumptions were as follows: 2016 2015 2014 Weighted-average assumptions used to determine benefit obligations at December 31: Discount Rate CECONY 4.00 % 4.05 % 3.75 % O&R 4.20 % 4.20 % 3.85 % Weighted-average assumptions used to determine net periodic benefit cost for the years ended December 31: Discount Rate CECONY 4.05 % 3.75 % 4.50 % O&R 4.20 % 3.85 % 4.75 % Expected Return on Plan Assets 7.00 % 7.75 % 7.75 % Refer to Note E for descriptions of the basis for determining the expected return on assets, investment policies and strategies and the assumed discount rate. The health care cost trend rate used to determine net periodic benefit cost for the year ended December 31, 2016 was 6.00 percent , which is assumed to decrease gradually to 4.50 percent by 2024 and remain at that level thereafter. The health care cost trend rate used to determine benefit obligations as of December 31, 2016 was 5.80 percent , which is assumed to decrease gradually to 4.50 percent by 2024 and remain at that level thereafter. A one-percentage point change in the assumed health care cost trend rate would have the following effects at December 31, 2016 : Con Edison CECONY 1-Percentage-Point (Millions of Dollars) Increase Decrease Increase Decrease Effect on accumulated other postretirement benefit obligation $(4) $26 $(24) $41 Effect on service cost and interest cost components for 2016 1 — (1) 1 Expected Benefit Payments Based on current assumptions, the Companies expect to make the following benefit payments over the next ten years , net of receipt of governmental subsidies: (Millions of Dollars) 2017 2018 2019 2020 2021 2022-2026 Con Edison $86 $85 $83 $80 $78 $375 CECONY 77 75 73 70 68 322 Expected Contributions Based on estimates as of December 31, 2016 , Con Edison and CECONY expect to make a contribution of $14 million (of which $10 million is to be contributed by CECONY) to the other postretirement benefit plans in 2017 . The Companies’ policy is to fund the total periodic benefit cost of the plans to the extent tax deductible. Plan Assets The asset allocations for CECONY’s other postretirement benefit plans at the end of 2016 , 2015 and 2014 , and the target allocation for 2017 are as follows: Target Allocation Range Plan Assets at December 31, Asset Category 2017 2016 2015 2014 Equity Securities 57%-73% 60 % 59 % 59 % Debt Securities 26%-44% 40 % 41 % 41 % Total 100% 100 % 100 % 100 % Con Edison has established postretirement health and life insurance benefit plan trusts for the investment of assets to be used for the exclusive purpose of providing other postretirement benefits to participants and beneficiaries. Refer to Note E for a discussion of Con Edison’s investment policy for its benefit plans. The fair values of the plan assets at December 31, 2016 by asset category as defined by the accounting rules for fair value measurements (see Note P) are as follows: (Millions of Dollars) Level 1 Level 2 Total Equity (a) $— $391 $391 Other Fixed Income Debt (b) — 250 250 Cash and Cash Equivalents (c) — 13 13 Total investments $— $654 $654 Funds for retiree health benefits (d) 165 105 270 Investments (including funds for retiree health benefits) $165 $759 $924 Funds for retiree health benefits measured at net asset value (d)(e) 37 Pending activities (f) 14 Total fair value of plan net assets $975 (a) Equity includes a passively managed commingled index fund benchmarked to the MSCI All Country World Index. (b) Other Fixed Income Debt includes a passively managed commingled index fund benchmarked to the Barclays Capital Aggregate Index. (c) Cash and Cash Equivalents include short term investments and money markets. (d) The Companies set aside funds for retiree health benefits through a separate account within the pension trust, as permitted under Section 401(h) of the Internal Revenue Code of 1986, as amended. In accordance with the Code, the plan’s investments in the 401(h) account may not be used for, or diverted to, any purpose other than providing health benefits for retirees. The net assets held in the 401(h) account are calculated based on a pro-rata percentage allocation of the net assets in the pension plan. The related obligations for health benefits are not included in the pension plan’s obligations and are included in the Companies’ other postretirement benefit obligation. See Note E. (e) In accordance with ASU 2015-07, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. See Note E. (f) Pending activities include security purchases and sales that have not settled, interest and dividends that have not been received, and reflects adjustments for available estimates at year end. The fair values of the plan assets at December 31, 2015 by asset category (see Note P) are as follows: (Millions of Dollars) Level 1 Level 2 Total Equity (a) $— $393 $393 Other Fixed Income Debt (b) — 260 260 Cash and Cash Equivalents (c) — 7 7 Total investments $— $660 $660 Funds for retiree health benefits (d) 162 120 282 Investments (including funds for retiree health benefits) $162 $780 $942 Funds for retiree health benefits measured at net asset value (d)(e) 43 Pending activities (f) 9 Total fair value of plan net assets $994 (a) - (f) Reference is made to footnotes (a) through (f) in the above table of other postretirement benefit plan assets at December 31, 2016 by asset category. Mortality Table Revision The Companies adopted revised mortality tables effective December 31, 2014 in the measurement of its pension and other postretirement benefit plan obligations, accounting costs, and required contribution amounts as discussed in Note E. As a result of the adoption, Con Edison recognized an increase of less than $10 million in its other postretirement benefits obligation as of December 31, 2014. The Companies, under their current New York rate plans, defer as a regulatory asset or liability, as the case may be, the differences between the actual level of expenses for pension and other postretirement benefits and amounts for those expenses reflected in rates.

Environmental Matters

Environmental Matters	12 Months Ended
	Dec. 31, 2016
Environmental Remediation Obligations [Abstract]
Environmental Matters	Environmental Matters Superfund Sites Hazardous substances, such as asbestos, polychlorinated biphenyls (PCBs) and coal tar, have been used or generated in the course of operations of the Utilities and their predecessors and are present at sites and in facilities and equipment they currently or previously owned, including sites at which gas was manufactured or stored. The Federal Comprehensive Environmental Response, Compensation and Liability Act of 1980 and similar state statutes (Superfund) impose joint and several liability, regardless of fault, upon generators of hazardous substances for investigation and remediation costs (which include costs of demolition, removal, disposal, storage, replacement, containment and monitoring) and natural resource damages. Liability under these laws can be material and may be imposed for contamination from past acts, even though such past acts may have been lawful at the time they occurred. The sites at which the Utilities have been asserted to have liability under these laws, including their manufactured gas plant sites and any neighboring areas to which contamination may have migrated, are referred to herein as “Superfund Sites.” For Superfund Sites where there are other potentially responsible parties and the Utilities are not managing the site investigation and remediation, the accrued liability represents an estimate of the amount the Utilities will need to pay to investigate and, where determinable, discharge their related obligations. For Superfund Sites (including the manufactured gas plant sites) for which one of the Utilities is managing the investigation and remediation, the accrued liability represents an estimate of the company’s share of the undiscounted cost to investigate the sites and, for sites that have been investigated in whole or in part, the cost to remediate the sites, if remediation is necessary and if a reasonable estimate of such cost can be made. Remediation costs are estimated in light of the information available, applicable remediation standards and experience with similar sites. The accrued liabilities and regulatory assets related to Superfund Sites at December 31, 2016 and 2015 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Accrued Liabilities: Manufactured gas plant sites $664 $679 $567 $579 Other Superfund Sites 89 86 88 86 Total $753 $765 $655 $665 Regulatory assets $823 $904 $711 $800 Most of the accrued Superfund Site liability relates to sites that have been investigated, in whole or in part. However, for some of the sites, the extent and associated cost of the required remediation has not yet been determined. As investigations progress and information pertaining to the required remediation becomes available, the Utilities expect that additional liability may be accrued, the amount of which is not presently determinable but may be material. The Utilities are permitted to recover or defer as regulatory assets (for subsequent recovery through rates) prudently incurred site investigation and remediation costs. Environmental remediation costs incurred and insurance recoveries received related to Superfund Sites at December 31, 2016 and 2015 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Remediation costs incurred $34 $37 $21 $34 Insurance recoveries received (a) 1 — 1 — (a) Reduced amount deferred for recovery from customers Con Edison and CECONY estimate that in 2017 they will incur costs for remediation of approximately $55 million and $47 million , respectively. The Companies are unable to estimate the time period over which the remaining accrued liability will be incurred because, among other things, the required remediation has not been determined for some of the sites. In 2016 , Con Edison and CECONY estimated that for their manufactured gas plant sites (including CECONY’s Astoria site), the aggregate undiscounted potential liability for the investigation and remediation of coal tar and/or other environmental contaminants could range up to $2.8 billion and $2.6 billion , respectively. These estimates were based on the assumption that there is contamination at all sites, including those that have not yet been fully investigated and additional assumptions about the extent of the contamination and the type and extent of the remediation that may be required. Actual experience may be materially different. Asbestos Proceedings Suits have been brought in New York State and federal courts against the Utilities and many other defendants, wherein a large number of plaintiffs sought large amounts of compensatory and punitive damages for deaths and injuries allegedly caused by exposure to asbestos at various premises of the Utilities. The suits that have been resolved, which are many, have been resolved without any payment by the Utilities, or for amounts that were not, in the aggregate, material to them. The amounts specified in all the remaining thousands of suits total billions of dollars; however, the Utilities believe that these amounts are greatly exaggerated, based on the disposition of previous claims. At December 31, 2016 , Con Edison and CECONY have accrued their estimated aggregate undiscounted potential liabilities for these suits and additional suits that may be brought over the next 15 years as shown in the following table. These estimates were based upon a combination of modeling, historical data analysis and risk factor assessment. Courts have begun, and unless otherwise determined on appeal may continue, to apply different standards for determining liability in asbestos suits than the standard that applied historically. As a result, the Companies currently believe that there is a reasonable possibility of an exposure to loss in excess of the liability accrued for the suits. The Companies are unable to estimate the amount or range of such loss. In addition, certain current and former employees have claimed or are claiming workers’ compensation benefits based on alleged disability from exposure to asbestos. CECONY is permitted to defer as regulatory assets (for subsequent recovery through rates) costs incurred for its asbestos lawsuits and workers’ compensation claims. The accrued liability for asbestos suits and workers’ compensation proceedings (including those related to asbestos exposure) and the amounts deferred as regulatory assets for the Companies at December 31, 2016 and 2015 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Accrued liability – asbestos suits $8 $8 $7 $7 Regulatory assets – asbestos suits $8 $8 $7 $7 Accrued liability – workers’ compensation $88 $86 $83 $81 Regulatory assets – workers’ compensation $13 $11 $13 $11

Other Material Contingencies

Other Material Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Other Material Contingencies	10 years Total (Millions of Dollars) Con Edison Transmission $435 $613 $— $1,048 Energy transactions 603 35 98 736 Renewable electric production projects 439 — 19 458 Other 128 — — 128 Total $1,605 $648 $117 $2,370 Con Edison Transmission – Con Edison has guaranteed payment by CET Electric of the contributions CET Electric agreed to make to New York Transco LLC (NY Transco). CET Electric acquired a 45.7 percent interest in NY Transco when it was formed in 2014. In May 2016, the transmission owners transferred certain projects to NY Transco, as to which CET Electric made its required contributions. The other projects that were proposed when NY Transco was formed remain subject to certain authorizations from the NYSPSC, the FERC and, as applicable, other federal, state and local agencies. Guarantee amount shown is for the maximum possible required amount of CET Electric's contributions for these other projects as calculated based on the assumptions that the projects are completed at 175 percent of their estimated costs and NY Transco does not use any debt financing for the projects. Guarantee term shown is assumed as the timing of the contributions is not certain. Also included within the table above is a guarantee for $25 million from Con Edison on behalf of CET Gas in relation to a proposed gas transmission project in West Virginia and Virginia. See Note U. Energy Transactions — Con Edison guarantees payments on behalf of the Clean Energy Businesses in order to facilitate physical and financial transactions in electricity, gas, pipeline capacity, transportation, oil, renewable energy credits and energy services. To the extent that liabilities exist under the contracts subject to these guarantees, such liabilities are included in Con Edison’s consolidated balance sheet. Guarantee amounts shown above include $42 million of guarantees or other credit support provided by Con Edison on behalf of Con Edison Solutions that may continue in effect during the period in which Con Edison Solutions provides transition services in connection with the retail electric supply business it sold in September 2016. See Note U. As part of the sale agreement, the purchaser has agreed to pay Con Edison Solutions for draws on such guarantees or other credit support. Renewable Electric Production Projects – Con Edison, Con Edison Development and Con Edison Solutions guarantee payments associated with the investment in solar and wind energy facilities on behalf of their wholly-owned subsidiaries. Other – Other guarantees include $70 million in guarantees provided by Con Edison to Travelers Insurance Company for indemnity agreements for surety bonds in connection with operation of solar energy facilities and energy service projects of Con Edison Development and Con Edison Solutions, respectively. Other guarantees also includes Con Edison's guarantee (subject to a $53 million maximum amount) of certain obligations of Con Edison Solutions under its agreement to sell its retail electric supply business. See Note U. In addition, Con Edison issued a guarantee estimated at $5 million to the Public Utility Commission of Texas covering obligations of Con Edison Solutions as a retail electric provider. As part of the sale agreement for the retail electric supply business discussed above, the purchaser has agreed to pay Con Edison Solutions for draws on the guarantee to the Public Utility Commission of Texas." id="sjs-B4">Other Material Contingencies Manhattan Steam Main Rupture In July 2007, a CECONY steam main located in midtown Manhattan ruptured. It has been reported that one person died and others were injured as a result of the incident. Several buildings in the area were damaged. Debris from the incident included dirt and mud containing asbestos. The response to the incident required the closing of several buildings and streets for various periods. Approximately sixty suits are pending against the company seeking generally unspecified compensatory and, in some cases, punitive damages, for wrongful death, personal injury, property damage and business interruption. The company has notified its insurers of the incident and believes that the policies in force at the time of the incident will cover the company’s costs to satisfy its liability to others in connection with the suits. In the company’s estimation, there is not a reasonable possibility that an exposure to loss exists for the suits that is materially in excess of the estimated liability accrued. At December 31, 2016 , the company has accrued its estimated liability for the suits of $25 million and an insurance receivable of $25 million . Manhattan Explosion and Fire On March 12, 2014, two multi-use five-story tall buildings located on Park Avenue between 116th and 117th Street in Manhattan were destroyed by an explosion and fire. CECONY had delivered gas to the buildings through service lines from a distribution main located below ground on Park Avenue. Eight people died and more than 50 people were injured. Additional buildings were also damaged. The National Transportation Safety Board (NTSB) investigated. The parties to the investigation included the company, the City of New York, the Pipeline and Hazardous Materials Safety Administration and the NYSPSC (which also conducted an investigation). In June 2015, the NTSB issued a final report concerning the incident, its probable cause and safety recommendations. The NTSB determined that the probable cause of the incident was (1) the failure of a defective fusion joint at a service tee (which joined a plastic service line to a plastic distribution main) installed by the company that allowed gas to leak from the distribution main and migrate into a building where it ignited and (2) a breach in a City sewer line that allowed groundwater and soil to flow into the sewer, resulting in a loss of support for the distribution main, which caused it to sag and overstressed the defective fusion joint. The NTSB also made safety recommendations, including recommendations to the company that addressed its procedures for the preparation and examination of plastic fusions, training of its staff on conditions for notifications to the City’s Fire Department and extension of its gas main isolation valve installation program. Approximately seventy suits are pending against the company seeking generally unspecified damages and, in some cases, punitive damages, for wrongful death, personal injury, property damage and business interruption. The company has notified its insurers of the incident and believes that the policies in force at the time of the incident will cover the company’s costs, in excess of a required retention (the amount of which is not material), to satisfy any liability it may have for damages in connection with the incident. The company is unable to estimate the amount or range of its possible loss for damages related to the incident. At December 31, 2016 , the company had not accrued a liability for damages related to the incident. Other Contingencies See “Other Regulatory Matters” in Note B and "Uncertain Tax Positions" in Note L. Guarantees Con Edison and its subsidiaries enter into various agreements providing financial or performance assurance primarily to third parties on behalf of their subsidiaries. Maximum amounts guaranteed by Con Edison totaled $2,370 million and $2,856 million at December 31, 2016 and 2015 , respectively. A summary, by type and term, of Con Edison’s total guarantees at December 31, 2016 is as follows: Guarantee Type 0 – 3 years 4 – 10 years > 10 years Total (Millions of Dollars) Con Edison Transmission $435 $613 $— $1,048 Energy transactions 603 35 98 736 Renewable electric production projects 439 — 19 458 Other 128 — — 128 Total $1,605 $648 $117 $2,370 Con Edison Transmission – Con Edison has guaranteed payment by CET Electric of the contributions CET Electric agreed to make to New York Transco LLC (NY Transco). CET Electric acquired a 45.7 percent interest in NY Transco when it was formed in 2014. In May 2016, the transmission owners transferred certain projects to NY Transco, as to which CET Electric made its required contributions. The other projects that were proposed when NY Transco was formed remain subject to certain authorizations from the NYSPSC, the FERC and, as applicable, other federal, state and local agencies. Guarantee amount shown is for the maximum possible required amount of CET Electric's contributions for these other projects as calculated based on the assumptions that the projects are completed at 175 percent of their estimated costs and NY Transco does not use any debt financing for the projects. Guarantee term shown is assumed as the timing of the contributions is not certain. Also included within the table above is a guarantee for $25 million from Con Edison on behalf of CET Gas in relation to a proposed gas transmission project in West Virginia and Virginia. See Note U. Energy Transactions — Con Edison guarantees payments on behalf of the Clean Energy Businesses in order to facilitate physical and financial transactions in electricity, gas, pipeline capacity, transportation, oil, renewable energy credits and energy services. To the extent that liabilities exist under the contracts subject to these guarantees, such liabilities are included in Con Edison’s consolidated balance sheet. Guarantee amounts shown above include $42 million of guarantees or other credit support provided by Con Edison on behalf of Con Edison Solutions that may continue in effect during the period in which Con Edison Solutions provides transition services in connection with the retail electric supply business it sold in September 2016. See Note U. As part of the sale agreement, the purchaser has agreed to pay Con Edison Solutions for draws on such guarantees or other credit support. Renewable Electric Production Projects – Con Edison, Con Edison Development and Con Edison Solutions guarantee payments associated with the investment in solar and wind energy facilities on behalf of their wholly-owned subsidiaries. Other – Other guarantees include $70 million in guarantees provided by Con Edison to Travelers Insurance Company for indemnity agreements for surety bonds in connection with operation of solar energy facilities and energy service projects of Con Edison Development and Con Edison Solutions, respectively. Other guarantees also includes Con Edison's guarantee (subject to a $53 million maximum amount) of certain obligations of Con Edison Solutions under its agreement to sell its retail electric supply business. See Note U. In addition, Con Edison issued a guarantee estimated at $5 million to the Public Utility Commission of Texas covering obligations of Con Edison Solutions as a retail electric provider. As part of the sale agreement for the retail electric supply business discussed above, the purchaser has agreed to pay Con Edison Solutions for draws on the guarantee to the Public Utility Commission of Texas.

Electricity Purchase Agreements

Electricity Purchase Agreements	12 Months Ended
	Dec. 31, 2016
Regulated Operations [Abstract]
Electricity Purchase Agreements	Regulatory Matters Rate Plans The Utilities provide service to New York customers according to the terms of tariffs approved by the NYSPSC. Tariffs for service to customers of Rockland Electric Company (RECO), O&R’s New Jersey regulated utility subsidiary, are approved by the New Jersey Board of Public Utilities (NJBPU). The tariffs include schedules of rates for service that limit the rates charged by the Utilities to amounts that recover from their customers costs approved by the regulator, including capital costs, of providing service to customers as defined by the tariff. The tariffs implement rate plans adopted by state utility regulators in rate orders issued at the conclusion of rate proceedings. Pursuant to the Utilities’ rate plans, there generally can be no change to the charges to customers during the respective terms of the rate plans other than specified adjustments provided for in the rate plans. The Utilities’ rate plans each cover specified periods, but rates determined pursuant to a plan generally continue in effect until a new rate plan is approved by the state utility regulator. Common provisions of the Utilities’ New York rate plans include: Recoverable energy costs that allow the Utilities to recover on a current basis the costs for the energy they supply with no mark-up to their full-service customers. Cost reconciliations that reconcile pension and other postretirement benefit costs, environmental remediation costs, property taxes, variable rate tax-exempt debt and certain other costs to amounts reflected in delivery rates for such costs. Utilities generally retain the right to petition for recovery or accounting deferral of extraordinary and material cost increases and provision is sometimes made for the utility to retain a share of cost reductions, for example, property tax refunds. Revenue decoupling mechanisms that reconcile actual energy delivery revenues to the authorized delivery revenues approved by the NYSPSC. The difference is accrued with interest for refund to, or recovery from customers, as applicable. Earnings sharing that require the Utilities to defer for customer benefit a portion of earnings over specified rates of return on common equity. There is no symmetric mechanism for earnings below specified rates of return on common equity. Negative revenue adjustments for failure to meet certain performance standards relating to service, reliability, safety and other matters. Net utility plant reconciliations that require deferral as a regulatory liability of the revenue requirement impact of the amount, if any, by which actual average net utility plant balances are less than amounts reflected in rates. Rate base is, in general, the sum of the Utilities’ net plant and working capital less deferred taxes. For each rate plan, the NYSPSC uses a forecast of the average rate base for each year that new rates would be in effect (“rate year”). Weighted average cost of capital is determined based on the authorized common equity ratio, return on common equity, cost of long-term debt and customer deposits reflected in each rate plan. For each rate plan, the revenues designed to provide the utility a return on invested capital for each rate year are determined by multiplying each utility rate base by its pre-tax weighted average cost of capital. The Utilities’ actual return on common equity will reflect their actual operations for each rate year, and may be more or less than the authorized return on equity reflected in their rate plans (and if more, may be subject to earnings sharing). The following tables contain a summary of the Utilities’ rate plans: CECONY – Electric Effective period January 2014 – December 2016 January 2017 - December 2019 (b) Base rate changes Yr. 1 – $(76.2) million (a) Yr. 1 - $195 million (b) Amortizations to income of net regulatory (assets) and liabilities Yr. 1 and 2 – $(37) million (c) Yr. 1 - $84 million Other revenue sources Retention of $90 million of annual transmission congestion revenues. Retention of $75 million of annual transmission congestion revenues. Revenue decoupling mechanisms In 2014, 2015 and 2016, the company deferred for customer benefit $146 million, $98 million and $101 million of revenues, respectively. Continuation of reconciliation of actual to authorized electric delivery revenues. Recoverable energy costs (d) Current rate recovery of purchased power and fuel costs. Continuation of current rate recovery of purchased power and fuel costs. Negative revenue adjustments Potential penalties (up to $400 million annually) if certain performance targets are not met. In 2014, the company recorded a $5 million negative revenue adjustment. In 2015 and 2016, the company did not record any negative revenue adjustments. Potential penalties if certain performance targets relating to service, reliability, safety and other matters are not met: Cost reconciliations In 2014, 2015 and 2016, the company deferred $57 million, $26 million and $68 million of net regulatory liabilities, respectively (e). Continuation of reconciliation of expenses for pension and other postretirement benefits, variable-rate tax-exempt debt, major storms, property taxes(e), municipal infrastructure support costs(f), the impact of new laws and environmental site investigation and remediation to amounts reflected in rates.(g) Net utility plant reconciliations Target levels reflected in rates were: Target levels reflected in rates: Average rate base Yr. 1 – $17,323 million Yr. 1 - $18,902 million Weighted average cost of capital (after-tax) Yr. 1 – 7.05 percent Yr. 1 - 6.82 percent Authorized return on common equity Yrs. 1 and 2 – 9.2 percent 9.0 percent Earnings sharing Most earnings above an annual earnings threshold of 9.8 percent for Yrs. 1 and 2 and 9.6 percent for Yr. 3 are to be applied to reduce regulatory assets for environmental remediation and other costs. In 2014 the company had no earnings above the threshold. Actual earnings were $44.4 million and $6.5 million above the threshold for 2015 and 2016, respectively. Most earnings above an annual earnings threshold of 9.5 percent are to be applied to reduce regulatory assets for environmental remediation and other costs accumulated in the rate year. Cost of long-term debt Yr. 1 – 5.17 percent Yr. 1 - 4.93 percent Common equity ratio 48 percent 48 percent (a) The impact of these base rate changes was deferred which resulted in a $30 million regulatory liability at December 31, 2015; this amount has been amortized to $0 at December 31, 2016. (b) In January 2017, the NYSPSC approved the September 2016 Joint Proposal for CECONY's electric rate plan for January 2017 through December 2019. The electric base rate increases are in addition to a $48 million increase resulting from the December 2016 expiration of a temporary credit under the prior rate plan. At the NYSPSC’s option, these increases are being implemented with increases of $199 million in each rate year. Base rates reflect recovery by the company of certain costs of its energy efficiency, system peak reduction and electric vehicle programs (Yr. 1 - $20.5 million ; Yr. 2 - $49 million ; and Yr. 3 - $107.5 million ) over a ten -year period, including the overall pre-tax rate of return on such costs. (c) Amounts reflect annual amortization of $107 million of the regulatory asset for deferred Superstorm Sandy and other major storm costs. The costs recoverable from customers were reduced by $4 million . The costs are no longer subject to NYSPSC staff review and the recovery of the costs is no longer subject to refund. In 2016, an additional $123 million of net regulatory liabilities were amortized to income. (d) For transmission service provided pursuant to the open access transmission tariff of PJM Interconnection LLC (PJM), unless and until changed by the NYSPSC, the company will recover all charges incurred associated with the transmission service. Starting in January 2014, PJM submitted to the FERC a series of requests that substantially increase the charges for the transmission service. CECONY has challenged each of these requests. To date, FERC has rejected all but one of CECONY’s protests. In April 2016, CECONY notified PJM that it will not be exercising its option to continue the service beyond April 2017. CECONY is continuing to challenge FERC’s approval of the increased charges that are being incurred through the end of the current contract term. In June 2015 and May 2016, CECONY filed appeals of certain FERC decisions with the U.S. Court of Appeals. (e) Deferrals for property taxes are limited to 90 percent of the difference from amounts reflected in rates, subject to an annual maximum for the remaining difference of not more than a maximum number of basis points (5.0, 7.5 or 10.0 basis points, depending on the year). (f) In general, if actual expenses for municipal infrastructure support (other than company labor) are below the amounts reflected in rates the company will defer the difference for credit to customers, and if the actual expenses are above the amount reflected in rates the company will defer for recovery from customers 80 percent of the difference subject to a maximum deferral of 30 percent of the amount reflected in rates. (g) In addition, amounts reflected in rates relating to the regulatory asset for future income tax and the excess deferred federal income tax liability are subject to reconciliation. The NYSPSC staff is to audit the regulatory asset and the tax liability. Differences resulting from the NYSPSC staff review will be deferred for NYSPSC determination of any amounts to be refunded or collected from customers. CECONY – Gas Effective period January 2014 – December 2016 January 2017 - December 2019 (b) Base rate changes Yr. 1 – $(54.6) million (a) Yr. 1 - $(5) million (b) Amortizations to income of net regulatory (assets) and liabilities $4 million over three years Yr. 1 - $39 million Other revenue sources Retention of revenues from non-firm customers of up to $65 million and 15 percent of any such revenues above $65 million. The company retained $70 million, $66 million and $65 million of such revenues in 2014, 2015 and 2016, respectively. Retention of annual revenues from non-firm customers of up to $65 million and 15 percent of any such revenues above $65 million. Revenue decoupling mechanisms In 2014, 2015 and 2016, the company deferred $28 million, $54 million and $71 million of regulatory liabilities, respectively. Continuation of reconciliation of actual to authorized gas delivery revenues. Recoverable energy costs Current rate recovery of purchased gas costs. Continuation of current rate recovery of purchased gas costs. Negative revenue adjustments Potential penalties (up to $33 million in 2014, $44 million in 2015, and $56 million in 2016) if certain gas performance targets are not met. In 2014, 2015 and 2016, the company did not record any negative revenue adjustments. Potential penalties if performance targets relating to service, safety and other matters are not met: Cost reconciliations In 2014, 2015 and 2016, the company deferred $38 million, $11 million, and $32 million of net regulatory liabilities, respectively. (c) Continuation of reconciliation of expenses for pension and other postretirement benefits, variable-rate tax-exempt debt, major storms, property taxes, municipal infrastructure support costs, the impact of new laws and environmental site investigation and remediation to amounts reflected in rates.(d) Net utility plant reconciliations Target levels reflected in rates were: Target levels reflected in rates: Average rate base Yr. 1 – $3,521 million Yr. 1 - $4,841 million Weighted average cost of capital Yr. 1 – 7.10 percent Yr. 1 - 6.82 percent Authorized return on common equity 9.3 percent 9.0 percent Earnings sharing Most earnings above an annual earnings threshold of 9.9 percent are to be applied to reduce regulatory assets for environmental remediation and other costs. In 2014, 2015 and 2016, the company had no earnings above the threshold. Most earnings above an annual earnings threshold of 9.5 percent are to be applied to reduce regulatory assets for environmental remediation and other costs accumulated in the rate year. Cost of long-term debt Yr. 1 – 5.17 percent Yr. 1 - 4.93 percent Common equity ratio 48 percent 48 percent (a) The impact of these base rate changes was deferred which resulted in a $32 million regulatory liability at December 31, 2016. (b) In January 2017, the NYSPSC approved the September 2016 Joint Proposal for CECONY's gas rate plan for January 2017 through December 2019. The gas base rate decrease is offset by a $41 million increase resulting from the December 2016 expiration of a temporary credit under the prior rate plan. (c) Deferrals for property taxes are limited to 90 percent of the difference from amounts reflected in rates, subject to an annual maximum for the remaining difference of not more than a 10 basis point impact on return on common equity (d) See footnotes (e), (f) and (g) to the table under "CECONY - Electric" above. CECONY – Steam Effective period January 2014 – December 2016 (a) Base rate changes Yr. 1 – $(22.4) million (b) Amortizations to income of net regulatory (assets) and liabilities $37 million over three years Recoverable energy costs Current rate recovery of purchased power and fuel costs. Negative revenue adjustments Potential penalties (up to $1 million annually) if certain steam performance targets are not met. In 2014, 2015 and 2016, the company did not record any negative revenue adjustments. Cost reconciliations (c) In 2014, 2015 and 2016, the company deferred $42 million of net regulatory liabilities, $17 million of net regulatory assets and $8 million of net regulatory liabilities, respectively. Net utility plant reconciliations Target levels reflected in rates were: Average rate base Yr. 1 – $1,511 million Weighted average cost of capital (after-tax) Yr. 1 – 7.10 percent Authorized return on common equity 9.3 percent Earnings sharing Weather normalized earnings above an annual earnings threshold of 9.9 percent are to be applied to reduce regulatory assets for environmental remediation and other costs. In 2014, the company had no earnings above the threshold. Actual earnings were $11.5 million and $7.8 million above the threshold in 2015 and 2016, respectively. Cost of long-term debt Yr. 1 – 5.17 percent Common equity ratio 48 percent (a) Rates determined pursuant to this rate plan continue in effect until a new rate plan is approved by the NYSPSC. (b) The impact of these base rate changes was deferred which resulted in an $8 million regulatory liability at December 31, 2016. (c) Deferrals for property taxes are limited to 90 percent of the difference from amounts reflected in rates, subject to an annual maximum for the remaining difference of not more than a 10 basis point impact on return on common equity. O&R New York – Electric Effective period July 2012 – June 2015 November 2015 - October 2017 Base rate changes Yr. 1 – $19.4 million Yr. 1 – $9.3 million – $8.8 million Amortizations to income of net regulatory (assets) and liabilities $(32.2) million over three years Yr. 1 – $(8.5) million (a) – $(9.4) million (a) Revenue decoupling mechanisms In 2012, 2013 and 2014, the company deferred for the customer’s benefit $2.6 million, $3.2 million and $(3.4) million, respectively. In 2015 and 2016, the company deferred for the customer’s benefit an immaterial amount and $6.3 million as regulatory liabilities, respectively. Recoverable energy costs Current rate recovery of purchased power and fuel costs. Continuation of current rate recovery of purchased power costs. Negative revenue adjustments Potential penalties (up to $3 million annually) if certain customer service and system reliability performance targets are not met. In 2012, 2013 and 2014, the company did not record any negative revenue adjustments. Potential penalties (up to $4 million annually) if certain performance targets are not met. In 2015 the company recorded $1.25 million in negative revenue adjustments. In 2016, the company did not record any negative revenue adjustments. Cost reconciliations In 2012, 2013 and 2014, the company deferred $7.8 million, $4.1 million and $(0.2) million as a net increase/(decrease) to regulatory assets, respectively. In 2015 and 2016, the company deferred $0.3 million and $7.4 million as net decreases to regulatory assets, respectively. Net utility plant reconciliations Target levels reflected in rates were: Target levels reflected in rates are: – $928 million (b) – $970 million (b) The company increased/(reduced) its regulatory asset by $2.2 million and $(1.9) million in 2015 and 2016, respectively. Average rate base Yr. 1 – $671 million Yr. 1 – $763 million – $805 million Weighted average cost of capital (after-tax) Yr. 1 – 7.61 percent Yr. 1 – 7.10 percent – 7.06 percent Authorized return on common equity Yr. 1 – 9.4 percent 9.0 percent Earnings sharing The company recorded a regulatory liability of $1 million for earnings above the sharing threshold under the rate plan as of December 31, 2014. Most earnings above an annual earnings threshold of 9.6 percent are to be applied to reduce regulatory assets. In 2015, earnings did not exceed the earnings threshold. Actual earnings were $6.1 million above the threshold for 2016. Cost of long-term debt Yr. 1 – 6.07 percent Yr. 1 – 5.42 percent – 5.35 percent Common equity ratio 48 percent 48 percent (a) $59.3 million of the regulatory asset for deferred storm costs is to be recovered from customers over a five year period, including $11.85 million in each of years 1 and 2, $1 million of the regulatory asset for such costs will not be recovered from customers, and all outstanding issues related to Superstorm Sandy and other past major storms prior to November 2014 are resolved. Approximately $4 million of regulatory assets for property tax and interest rate reconciliations will not be recovered from customers. Amounts that will not be recovered from customers were charged-off in June 2015. (b) Excludes electric AMI as to which the company will be required to defer as a regulatory liability the revenue requirement impact of the amount, if any, by which actual average net utility plant balances are less than amounts reflected in rates: $1 million in year 1 and $9 million in year 2. O&R New York – Gas Effective period November 2009 – December 2014 November 2015 – October 2018 Base rate changes Yr. 1 – $9 million Yr. 1 – $16.4 million – $16.4 million – $5.8 million – $10.6 million collected through a surcharge Amortization to income of net regulatory (assets) and liabilities $(2) million over three years Yr. 1 – $(1.7) million (a) – $(2.1) million (a) – $(2.5) million (a) Revenue decoupling mechanisms In 2012, 2013 and 2014, the company deferred $4.7 million, $0.7 million and $(0.1) million of regulatory liabilities, respectively. In 2015 and 2016, the company deferred $0.8 million regulatory assets and $6.2 million of regulatory liabilities, respectively. Recoverable energy costs Current rate recovery of purchased gas costs. Current rate recovery of purchased gas costs. Negative revenue adjustments Potential penalties (up to $1.4 million annually) if certain operations and customer service requirements are not met. In 2012, 2013 and 2014, the company did not record any negative revenue adjustments. Potential penalties (up to $3.7 million in Yr. 1, $4.7 million in Yr. 2 and $5.8 million in Yr. 3) if certain performance targets are not met. In 2015 and 2016, the company did not record any negative revenue adjustments. Cost reconciliations In 2012, 2013 and 2014, the company deferred $0.7 million, $8.3 million and $8.3 million as net regulatory assets, respectively. In 2015 and 2016, the company deferred $4.5 million and $6.6 million as net regulatory liabilities and assets, respectively. Net utility plant reconciliations The company deferred $0.7 million in 2012 as a regulatory asset and no deferrals were recorded for 2013 or 2014. Target levels reflected in rates are: – $492 million (b) – $518 million (b) – $546 million (b) No deferral was recorded for 2015 and an immaterial amount was recorded as a regulatory liability in 2016. Average rate base Yr. 1 – $280 million Yr. 1 – $366 million – $391 million – $417 million Weighted average cost of capital (after-tax) 8.49 percent Yr. 1 – 7.10 percent – 7.06 percent – 7.06 percent Authorized return on common equity 10.4 percent 9.0 percent Earnings sharing Earnings above an annual earnings threshold of 11.4 percent are to be applied to reduce regulatory assets. In 2012, 2013 and 2014, earnings did not exceed the earnings threshold. Most earnings above an annual earnings threshold of 9.6 percent are to be applied to reduce regulatory assets. In 2015, earnings did not exceed the earnings threshold. Actual earnings were $4 million above the threshold for 2016. Cost of long-term debt 6.81 percent Yr. 1 – 5.42 percent – 5.35 percent – 5.35 percent Common equity ratio 48 percent 48 percent (a) Reflects that the company will not recover from customers a total of approximately $14 million of regulatory assets for property tax and interest rate reconciliations. Amounts that will not be recovered from customers were charged-off in June 2015. (b) Excludes gas AMI as to which the company will be required to defer as a regulatory liability the revenue requirement impact of the amount, if any, by which actual average net utility plant balances are less than amounts reflected in rates: $0.5 million in year 1, $4.2 million in year 2 and $7.2 million in year 3. RECO Effective period May 2010 – July 2014 August 2014 – July 2015 (a) Base rate changes Yr. 1 – $9.8 million Yr. 1 – $13.0 million Amortization to income of net regulatory (assets) and liabilities $(3.9) million over four years and $(4.9) million of deferred storm costs over five years $0.4 million over three years and $(25.6) million of deferred storm costs over four years Recoverable energy costs Current rate recovery of purchased power costs. Current rate recovery of purchased power costs. Cost reconciliations None None Average rate base $148.6 million $172.2 million Weighted average cost of capital (after-tax) 8.21 percent 7.83 percent Authorized return on common equity 10.3 percent 9.75 percent Cost of long-term debt 6.16 percent 5.89 percent Common equity ratio 50 percent 50 percent (a) In January 2016, the NJBPU approved RECO’s plan for a 3 -year, $15.7 million electric system storm hardening capital program, the costs of which RECO, beginning in 2017, is collecting through a customer surcharge until a new rate plan is approved that reflects the costs. In February 2017, RECO, the staff of the NJBPU and other parties entered into a stipulation of settlement for a RECO electric rate plan for the period commencing March 2017. The stipulation is subject to NJBPU approval. The rate plan would provide for an electric rate increase of $1.7 million , reflecting a return on common equity of 9.6 percent and a common equity ratio of 49.7 percent , and for continuation of the provisions for recovery from customers of the cost of purchased power. In January 2017, RECO filed a request with FERC for an increase to its annual transmission revenue requirement from $11.8 million to $19.7 million , effective April 2017. The filing reflects a return on common equity of 10.7 percent and a common equity ratio of 48 percent . Other Regulatory Matters In June 2014, the NYSPSC initiated a proceeding to investigate the practices of qualifying persons to perform plastic fusions on gas facilities. New York State regulations require gas utilities to qualify and, except in certain circumstances, annually requalify workers that perform fusion to join plastic pipe. The NYSPSC directed the New York gas utilities to provide information in this proceeding about their compliance with the qualification and requalification requirements and related matters; their procedures for compliance with all gas safety regulations; and their annual chief executive officer certifications regarding these and other procedures. CECONY’s qualification and requalification procedures had not included certain required testing to evaluate specimen fuses. In addition, CECONY and O&R had not timely requalified certain workers that had been qualified under their respective procedures to perform fusion to join plastic pipe. CECONY and O&R have requalified their workers who perform plastic pipe fusions. In May 2015, the NYSPSC, which indicated that it would address enforcement at a later date, ordered CECONY, O&R and other gas utilities to perform risk assessment and remediation plans, additional leakage surveying and reporting; CECONY to hire an independent statistician to develop a risk assessment and remediation plan; and the gas utilities to implement certain new plastic fusion requirements. In December 2015, the NYSPSC staff informed O&R that the company had satisfactorily completed its risk assessment and remediation plan. CECONY is implementing the three -year risk assessment and remediation plan it submitted to the NYSPSC staff in October 2016. In November 2015, the NYSPSC ordered CECONY to show cause why the NYSPSC should not commence proceedings to penalize the company for alleged violations of gas safety regulations identified by the NYSPSC staff in its investigation of a March 2014 explosion and fire and to review the prudence of the company's conduct associated with the incident. See "Manhattan Explosion and Fire" in Note H. In December 2015, the company responded that the NYSPSC should not institute the proceedings and disputed the alleged violations. In February 2017, the NYSPSC approved a settlement agreement with CECONY related to the June 2014 plastic fusion proceeding and the November 2015 order to show cause. Pursuant to the settlement agreement, the company will not recover from customers $126 million of costs it incurred for gas emergency response activities in 2014, 2015 and 2016 in excess of amounts reflected in its gas rate plan for those years. At December 31, 2016, the company had not deferred any such incremental costs as a regulatory asset. In addition, the company will provide $27 million of future benefits to customers. At December 31, 2016, the Company had accrued a regulatory liability for these future benefits. Regulatory Assets and Liabilities Regulatory assets and liabilities at December 31, 2016 and 2015 were comprised of the following items: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Regulatory assets Unrecognized pension and other postretirement costs $2,874 $3,876 $2,730 $3,697 Future income tax 2,439 2,350 2,325 2,232 Environmental remediation costs 823 904 711 800 Revenue taxes 295 253 280 240 Deferred storm costs 56 185 3 110 Deferred derivative losses 48 50 42 46 Unamortized loss on reacquired debt 43 50 41 48 Recoverable energy costs 42 16 38 15 Pension and other postretirement benefits deferrals 38 45 7 16 O&R property tax reconciliation 37 46 — — Surcharge for New York State assessment 28 44 26 40 Preferred stock redemption 25 26 25 26 Net electric deferrals 24 44 24 44 O&R transition bond charges 15 21 — — Workers’ compensation 13 11 13 11 Other 224 175 208 157 Regulatory assets – noncurrent 7,024 8,096 6,473 7,482 Deferred derivative losses 91 113 86 103 Recoverable energy costs 9 19 4 18 Regulatory assets – current 100 132 90 121 Total Regulatory Assets $7,124 $8,228 $6,563 $7,603 Regulatory liabilities Allowance for cost of removal less salvage $755 $676 $641 $570 Pension and other postretirement benefit deferrals 193 76 162 46 Property tax reconciliation 178 303 178 303 Net unbilled revenue deferrals 145 109 145 109 Prudence proceeding 95 99 95 99 Carrying charges on repair allowance and bonus depreciation 68 49 67 48 New York State income tax rate change 61 75 60 72 Unrecognized other postretirement costs 60 28 60 28 Variable-rate tax-exempt debt - cost rate reconciliation 55 70 48 60 Base rate change deferrals 40 128 40 128 Earnings sharing - electric, gas and steam 39 80 28 80 Net utility plant reconciliations 16 32 15 31 Property tax refunds 1 44 1 44 World Trade Center settlement proceeds — 21 — 21 Other 199 187 172 150 Regulatory liabilities – noncurrent 1,905 1,977 1,712 1,789 Revenue decoupling mechanism 71 45 61 45 Refundable energy costs 29 64 5 33 Deferred derivative gains 28 6 24 6 Regulatory liabilities—current 128 115 90 84 Total Regulatory Liabilities $2,033 $2,092 $1,802 $1,873 Prudence proceeding represents the remaining amount to be credited to customers pursuant to a Joint Proposal, approved by the NYSPSC in April 2016, with respect to the prudence of certain CECONY expenditures and related matters. Unrecognized pension and other postretirement costs represent the net regulatory asset associated with the accounting rules for retirement benefits. See Note A. Deferred storm costs represent response and restoration costs, other than capital expenditures, in connection with Superstorm Sandy and other major storms that were deferred by the Utilities. Net electric deferrals represent the remaining unamortized balance of certain regulatory assets and liabilities of CECONY that were combined effective April 1, 2010 and are being amortized to income through March 31, 2018. Revenue taxes represent the timing difference between taxes collected and paid by the Utilities to fund mass transportation. The NYSPSC has authorized CECONY to accrue unbilled electric, gas and steam revenues. CECONY has deferred the net margin on the unbilled revenues for the future benefit of customers by recording a regulatory liability of $145 million and $109 million at December 31, 2016 and 2015 , respectively, for the difference between the unbilled revenues and energy cost liabilities. Electricity Purchase Agreements The Utilities have electricity purchase agreements with non-utility generators and others for generating capacity. The Utilities recover their purchased power costs in accordance with provisions approved by the applicable state public utility regulators. See “Recoverable Energy Costs” in Note A. At December 31, 2016 , the significant terms of the electricity purchase agreements with non-utility generators were as follows: Facility Equity Owner Plant Output (MW) Contracted Output (MW) Contract Start Date Contract Term (Years) Brooklyn Navy Yard Brooklyn Navy Yard Cogeneration Partners, LP 322 293 November 1996 40 Linden Cogeneration Cogen Technologies Linden Venture, LP 974 630 May 1992 25 Indian Point Entergy Nuclear Power Marketing, LLC 2,150 500 August 2001 16 The Utilities also conducted auctions and have entered into various other electricity purchase agreements. Assuming performance by the parties to the electricity purchase agreements, the Utilities are obligated over the terms of the agreements to make capacity and other fixed payments. The future capacity and other fixed payments under the contracts are estimated to be as follows: (Millions of Dollars) 2017 2018 2019 2020 2021 All Years Thereafter Con Edison $178 $125 $120 $76 $54 $710 CECONY 178 125 119 75 54 710 For energy delivered under most of the electricity purchase agreements, CECONY is obligated to pay variable prices. The company’s payments under the agreements for capacity, energy and other fixed payments in 2016 , 2015 and 2014 were as follows: For the Years Ended December 31, (Millions of Dollars) 2016 2015 2014 Linden Cogeneration $304 $323 $381 Indian Point 203 226 247 Astoria Energy (a) 50 178 230 Astoria Generating Company 16 — — Brooklyn Navy Yard 119 113 133 Indeck Corinth (b) — 25 80 Selkirk (c) — — 144 Independence (c) — — 97 Total $692 $865 $1,312 (a) Contract term ended in 2016. (b) Contract term ended in 2015. (c) Contract term ended in 2014

Leases

Leases	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Leases	Leases Con Edison’s subsidiaries lease electric transmission facilities, gas distribution facilities, land, office buildings and equipment. In accordance with the accounting rules for leases, these leases are classified as either capital leases or operating leases. Most of the operating leases provide the option to renew at the fair rental value for future periods. Generally, it is expected that leases will be renewed or replaced in the normal course of business. Capital leases: For ratemaking purposes capital leases are treated as operating leases; therefore, in accordance with the accounting rules for regulated operations, the amortization of the leased asset is based on the rental payments recovered from customers. The following assets under capital leases are included in the Companies’ consolidated balance sheets at December 31, 2016 and 2015 : Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 UTILITY PLANT Common $3 $3 $2 $2 The accumulated amortization of the capital leases for Con Edison and CECONY was $3 million and $1 million , respectively at December 31, 2016 , and $3 million and $2 million , respectively at December 31, 2015 . The future minimum lease commitments for the above assets are as follows: (Millions of Dollars) Con Edison CECONY 2017 $1 $1 2018 1 1 2019 — — 2020 — — 2021 — — All years thereafter — — Total 2 2 Less: amount representing interest — — Present value of net minimum lease payment $2 $2 Operating leases: The future minimum lease commitments under the Companies’ operating lease agreements that are not cancellable by the Companies are as follows: (Millions of Dollars) Con Edison CECONY 2017 $61 $53 2018 62 54 2019 61 54 2020 61 54 2021 58 53 All years thereafter 788 696 Total $1,091 $964 Substantially all of the amounts shown in the above table are estimated amounts payable under CECONY’s revocable consent agreement with New York City for the use of streets and public places for installation and operation of transformers and associated vaults and equipment. Under the agreement, payments by CECONY increase 2.18 percent annually and are subject to decrease if CECONY’s transformer installations decrease by ½ of 1 percent or more from the prior year. For information about changes to the accounting rules for leases, see Note T.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets In 2016 and 2015 , Con Edison completed impairment tests for its goodwill of $406 million related to the O&R merger, and determined that it was not impaired. For the impairment test, $245 million and $161 million of the goodwill were allocated to CECONY and O&R, respectively. In 2016 and 2015 , Con Edison completed impairment tests for the goodwill of $23 million related to two energy services companies owned by Con Edison Solutions and a gas storage company owned by Con Edison Development. In 2015 , Con Edison determined that the goodwill was not impaired. In 2016 , Con Edison determined that goodwill related to the two energy services companies was impaired and upon calculating the implied fair value of goodwill using fair values based primarily on discounted cash flows, recorded a corresponding impairment charge of $15 million ( $12 million , net of tax). In 2016, Con Edison determined that goodwill related to the gas storage company was not impaired. Additionally, in 2016, Con Edison Solutions acquired a residential solar company and recorded $14 million of goodwill as part of the preliminary purchase price allocation. Estimates of future cash flows, projected growth rates, and discount rates inherent in the cash flow estimates for the gas storage company and residential solar company may vary significantly from actual results, which could result in a future impairment of goodwill. For information about changes to the accounting rules for goodwill, see Note T. Con Edison's other intangible assets consist primarily of power purchase agreements, which were identified as part of purchase price allocations associated with acquisitions made by Con Edison Development in 2016 (see Note U). At December 31, 2016, intangible assets arising from power purchase agreements were $119 million , net of accumulated amortization of $1 million , and are being amortized over the life of each agreement. Excluding power purchase agreements, Con Edison’s other intangible assets were $5 million and $2 million , net of accumulated amortization of $5 million and $4 million , at December 31, 2016 and 2015, respectively. CECONY’s other intangible assets were immaterial at December 31, 2016 and 2015. Con Edison recorded amortization expense related to its intangible assets of $2 million in 2016, and immaterial amounts in 2015 and 2014. Con Edison expects amortization expense to be $8 million per year over the next five years.

Income Tax

Income Tax	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Tax	Income Tax The components of income tax are as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 State Current $(42) $38 $59 $(1) $48 $66 Deferred 188 93 61 114 82 65 Federal Current (43) (86) (9) 59 77 158 Deferred 604 569 463 435 372 271 Amortization of investment tax credits (9) (9) (6) (4) (5) (5) Total income tax expense $698 $605 $568 $603 $574 $555 The tax effects of temporary differences, which gave rise to deferred tax assets and liabilities, are as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Deferred tax liabilities: Property basis differences $9,446 $8,614 $8,620 $7,922 Regulatory assets: Unrecognized pension and other postretirement costs 1,162 1,562 1,104 1,490 Future income tax 986 947 940 899 Environmental remediation costs 333 365 287 322 Deferred storm costs 23 75 1 45 Other regulatory assets 371 367 321 308 Equity investments 363 295 — — Total deferred tax liabilities $12,684 $12,225 $11,273 $10,986 Deferred tax assets: Accrued pension and other postretirement costs $581 $982 $467 $857 Regulatory liabilities 822 836 728 752 Superfund and other environmental costs 304 308 265 268 Asset retirement obligations 99 97 92 94 Loss carryforwards 59 29 — — Tax credits carryforward 498 258 — 1 Valuation allowance (16) (15) — — Other 303 362 312 292 Total deferred tax assets 2,650 2,857 1,864 2,264 Net deferred tax liabilities $10,034 $9,368 $9,409 $8,722 Unamortized investment tax credits 171 169 41 33 Net deferred tax liabilities and unamortized investment tax credits $10,205 $9,537 $9,450 $8,755 Reconciliation of the difference between income tax expense and the amount computed by applying the prevailing statutory income tax rate to income before income taxes is as follows: Con Edison CECONY (% of Pre-tax income) 2016 2015 2014 2016 2015 2014 STATUTORY TAX RATE Federal 35 % 35 % 35 % 35 % 35 % 35 % Changes in computed taxes resulting from: State income tax 4 5 5 4 5 5 Cost of removal (1 ) (5 ) (5 ) (1 ) (5 ) (5 ) Renewable energy credits (1 ) (1 ) — — — — Research and development credits (1 ) — — (1 ) — — Other — — (1 ) (1 ) — (1 ) Effective tax rate 36 % 34 % 34 % 36 % 35 % 34 % In 2016, Con Edison had a federal net operating loss of approximately $204 million , primarily due to bonus depreciation. Con Edison expects to carryback approximately $178 million of its 2016 net operating loss to 2007 and 2014, which will result in recovery of $32 million of income tax and reestablishment of $31 million of general business tax credits. The remaining 2016 federal net operating loss of $26 million will be carried forward to future years and will not expire until 2036. General business tax credits that were generated in 2016 ( $207 million ) and became available as a result of the net operating loss carryback ( $31 million ) will be carried forward to future years. Con Edison has $498 million in general business tax credit (primarily renewable energy tax credits), which if unused will begin to expire in 2032. A deferred tax asset for these tax attribute carryforwards was recorded, and no valuation allowance has been provided, as it is more likely than not that the deferred tax asset will be realized. Con Edison recorded a full valuation allowance of $3 million in 2015 against its charitable contribution carryforward from 2011. Due to the expiration of this charitable contribution carryforward in 2016, Con Edison wrote off the deferred tax asset and corresponding valuation allowance. Charitable contributions carryforward of $5 million and $6 million for 2015 and 2016, respectively, that will expire in 2020 and 2021, respectively, were recorded as a deferred tax asset and no valuation allowance has been provided, as it is more likely than not that the deferred tax asset will be realized. In addition, a $12 million valuation allowance for New York City net operating loss carryforward and a $4 million valuation allowance for state net operating losses carryforward has been provided; as it is not more likely than not that the deferred tax asset will be realized. In 2014, tax legislation was enacted in the State of New York that reduced the corporate franchise tax rate from 7.1 percent to 6.5 percent , beginning January 1, 2016. The application of this legislation decreased Con Edison’s accumulated deferred tax liabilities by $74 million ( $69 million for CECONY), decreased Con Edison’s regulatory asset for future income tax by $11 million ( $10 million for CECONY) and increased Con Edison’s regulatory liability by $62 million ( $59 million for CECONY). The impact of this tax legislation on Con Edison’s effective tax rate was not material, and there was no impact on CECONY’s effective tax rate for the year ended December 31, 2014. Under the Taxpayer Relief Act of 2012, 50 percent bonus depreciation expired on December 31, 2013. The Tax Increase Prevention Act of 2014 extended bonus depreciation for another year through December 31, 2014. As a result of the extension of bonus depreciation to 2014, Con Edison filed a refund request with the IRS in January 2015 to recover $224 million ( $128 million for CECONY) in estimated federal tax payments and received the refund in March 2015. The Protecting Americans from Tax Hikes Act of 2015 extended bonus depreciation for property acquired and placed in service during 2015 through 2019. The bonus depreciation percentage is 50 percent for property placed in service during 2015, 2016 and 2017 and phases down to 40 percent in 2018, and 30 percent in 2019. As a result of the extension of bonus depreciation to 2015, Con Edison filed a refund request with the IRS in January 2016 to recover $160 million in estimated federal tax payment s. In February 2016, Con Edison received a refund of estimated taxes paid in the amount of $160 million ( $143 million for CECONY). Uncertain Tax Positions Under the accounting rules for income taxes, the Companies are not permitted to recognize the tax benefit attributable to a tax position unless such position is more likely than not to be sustained upon examination by taxing authorities, including resolution of any related appeals and litigation processes, based solely on the technical merits of the position. A reconciliation of the beginning and ending amounts of unrecognized tax benefits for Con Edison and CECONY follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 Balance at January 1, $34 $34 $9 $2 $2 $— Additions based on tax positions related to the current year 2 — — 2 — — Additions based on tax positions of prior years 19 1 27 19 — 2 Reductions for tax positions of prior years (13) — (2) (2) — — Reductions from expiration of statute of limitations — (1) — — — — Settlements — — — — — — Balance at December 31, $42 $34 $34 $21 $2 $2 In 2016, Con Edison reached a settlement with New York State on two claims it had filed in previous years and reversed $11 million in uncertain tax positions. Of this amount, $8 million ( $5 million , net of federal taxes) reduced Con Edison’s effective tax rate. The amount related to CECONY was $2 million ( $1 million , net of federal taxes), all of which reduced CECONY’s effective tax rate. Current year additions of $21 million are for tax credits and prior years' claims filed in 2016. As of December 31, 2016 , Con Edison reasonably expects to resolve within the next twelve months approximately $35 million ( $24 million , net of federal taxes) of various federal and state uncertainties due to the expected completion of ongoing tax examinations, including $21 million ( $14 million , net of federal taxes), which, if recognized, would reduce Con Edison’s effective tax rate. The amount related to CECONY is approximately $17 million ( $12 million , net of federal taxes), including $2 million , which, if recognized, would reduce CECONY’s effective tax rate. The Companies recognize interest on liabilities for uncertain tax positions in interest expense and would recognize penalties, if any, in operating expenses in the Companies’ consolidated income statements. In 2016 , 2015 and 2014 , the Companies recognized an immaterial amount of interest and no penalties for uncertain tax positions in their consolidated income statements. At December 31, 2016 and 2015 , the Companies recognized an immaterial amount of interest and no penalties in their consolidated balance sheets. At December 31, 2016 , the total amount of unrecognized tax benefits that, if recognized, would reduce the Companies’ effective tax rate is $24 million ( $17 million , net of federal taxes) with $3 million attributable to CECONY. The federal tax returns for 2012 through 2015 remain open for examination. State income tax returns remain open for examination in New York for tax years 2006 through 2015 and in New Jersey for tax years 2008 through 2015.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Companies may compensate employees and directors with, among other things, stock options, stock units, restricted stock units and contributions to the stock purchase plan. The Long Term Incentive Plan, which was approved by Con Edison’s shareholders in 2003 (2003 LTIP), and the Long Term Incentive Plan, which was approved by Con Edison’s shareholders in 2013 (2013 LTIP), are collectively referred to herein as the LTIP. The LTIP provides for, among other things, awards to employees of restricted stock units and stock options and, to Con Edison’s non-employee directors, stock units. Existing awards under the 2003 LTIP continue in effect, however no new awards may be issued under the 2003 LTIP. The 2013 LTIP provides for awards for up to five million shares of common stock. Shares of Con Edison common stock used to satisfy the Companies’ obligations with respect to stock-based compensation may be new (authorized, but unissued) shares, treasury shares or shares purchased in the open market. The shares used during the year ended December 31, 2016 were new shares. The Companies intend to use new shares to fulfill their stock-based compensation obligations for 2017 . The Companies recognized stock-based compensation expense using a fair value measurement method. The following table summarizes stock-based compensation expense recognized by the Companies in the years ended December 31, 2016 , 2015 and 2014 : Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 Performance-based restricted stock $42 $27 $22 $36 $23 $19 Time-based restricted stock 2 1 2 2 1 2 Non-employee director deferred stock compensation 2 2 2 2 2 2 Stock purchase plan 4 4 3 4 3 3 Total $50 $34 $29 $44 $29 $26 Income tax benefit $20 $14 $12 $18 $12 $10 Stock Options The Companies last granted stock options in 2006. The stock options generally vested over a three -year period and had a term of 10 years . Options were granted at an exercise price equal to the fair market value of a common share when the option was granted. The Companies generally recognized compensation expense (based on the fair value of stock option awards) over the vesting period. No outstanding options remain as of December 31, 2016 . A summary of changes in the status of stock options as of December 31, 2016 is as follows: Con Edison CECONY Shares Weighted Average Exercise Price Shares Weighted Average Exercise Price Outstanding at December 31, 2015 79,125 $43.50 65,775 $43.50 Exercised 79,125 43.50 65,775 43.50 Forfeited — — — — Outstanding at December 31, 2016 — $— — $— The following table summarizes information about stock options for the years ended December 31, 2016 and 2015 : Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Aggregate intrinsic value (a) Options outstanding $— $2 $— $1 Options exercised 2 3 2 3 Cash received by Con Edison for payment of exercise price 3 6 3 5 (a) Aggregate intrinsic value represents the changes in the fair value of all outstanding options from their grant dates to December 31 of the years presented above. The income tax benefit Con Edison realized from stock options exercised in the years ended December 31, 2016 , 2015 and 2014 was $1 million . Restricted Stock and Stock Units Restricted stock and stock unit awards under the LTIP have been made as follows: (i) awards that provide for adjustment of the number of units (performance-restricted stock units or Performance RSUs) to certain officers and employees; (ii) time-based awards to certain employees; and (iii) awards to non-employee directors. Restricted stock and stock units awarded represents the right to receive, upon vesting, shares of Con Edison common stock, or, except for units awarded under the directors’ plan, the cash value of shares or a combination thereof. The number of units in each annual Performance RSU award is subject to adjustment as follows: (i) 50 percent of the units awarded will be multiplied by a factor that may range from 0 to 200 percent , based on Con Edison’s total shareholder return relative to a specified peer group during a specified performance period (the TSR portion); and (ii) 50 percent of the units awarded will be multiplied by factors that may range from 0 to 200 percent, based on determinations made in connection with the Companies’ annual incentive plans or, for certain executive officers, actual performance as compared to certain performance measures during a specified performance period (the non-TSR portion). Performance RSU awards generally vest upon completion of the performance period. Performance against the established targets is recomputed each reporting period as of the earlier of the reporting date and the vesting date. The TSR portion applies a Monte Carlo simulation model, and the non-TSR portion is the product of the market price at the end of the period and the average non-TSR determination over the vesting period. Performance RSUs are “liability awards” because each Performance RSU represents the right to receive, upon vesting, one share of Con Edison common stock, the cash value of a share or a combination thereof. As such, changes in the fair value of the Performance RSUs are reflected in net income. The assumptions used to calculate the fair value of the awards were as follows: 2016 2015 2014 Risk-free interest rate (a) 0.85% - 1.20% 0.64% - 3.28% 0.23% - 3.07% Expected term (b) 3 years 3 years 3 years Expected share price volatility (c) 17.72% - 18.22% 15.82% 13.14% (a) The risk-free rate is based on the U.S. Treasury zero-coupon yield curve. (b) The expected term of the Performance RSUs equals the vesting period. The Companies do not expect significant forfeitures to occur. (c) Based on historical experience. A summary of changes in the status of the Performance RSUs’ TSR and non-TSR portions during the year ended December 31, 2016 is as follows: Con Edison CECONY Weighted Average Grant Date Fair Value (a) Weighted Average Grant Date Fair Value (a) Units TSR Portion (b) Non-TSR Portion (c) Units TSR Portion (b) Non-TSR Portion (c) Non-vested at December 31, 2015 1,078,339 $45.26 $58.08 853,257 $45.37 $58.12 Granted 386,400 83.16 72.10 295,300 82.73 72.34 Vested (351,230) 55.16 57.96 (285,162) 55.21 58.07 Forfeited (26,372) 48.48 61.03 (15,053) 53.61 63.05 Non-vested at December 31, 2016 1,087,137 $55.45 $63.03 848,342 $54.92 $63.00 (a) The TSR and non-TSR Portions each account for 50 percent of the awards’ value. (b) Fair value is determined using the Monte Carlo simulation described above. Weighted average grant date fair value does not reflect any accrual or payment of dividends prior to vesting. (c) Fair value is determined using the market price of one share of Con Edison common stock on the grant date. The market price has not been discounted to reflect that dividends do not accrue and are not payable on Performance RSUs until vesting. The total expense to be recognized by Con Edison in future periods for unvested Performance RSUs outstanding at December 31, 2016 is $34 million , including $27 million for CECONY, and is expected to be recognized over a weighted average period of one year for both Con Edison and CECONY. In accordance with the accounting rules for stock compensation, for time-based awards, the Companies are accruing a liability and recognizing compensation expense based on the market value of a common share throughout the vesting period. The vesting period for awards is three years and is based on the employee’s continuous service to Con Edison. Prior to vesting, the awards are subject to forfeiture in whole or in part under certain circumstances. The awards are “liability awards” because each restricted stock unit represents the right to receive, upon vesting, one share of Con Edison common stock, the cash value of a share or a combination thereof. As such, prior to vesting, changes in the fair value of the units are reflected in net income. A summary of changes in the status of time-based awards during the year ended December 31, 2016 is as follows: Con Edison CECONY Units Weighted Average Grant Date Fair Value Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 64,980 $58.56 61,630 $58.55 Granted 23,000 76.62 21,800 76.62 Vested (20,900) 61.03 (19,800) 61.03 Forfeited (1,100) 60.13 (1,050) 60.43 Non-vested at December 31, 2016 65,980 $64.04 62,580 $64.03 The total expense to be recognized by Con Edison in future periods for unvested time-based awards outstanding at December 31, 2016 for Con Edison and CECONY was $2 million and is expected to be recognized over a weighted average period of one year . Under the LTIP, each non-employee director receives stock units, which are deferred until the director’s separation from service or another date specified by the director. Each director may also elect to defer all or a portion of their cash compensation into additional stock units, which are deferred until the director’s termination of service or another date specified by the director. Non-employee directors’ stock units issued under the LTIP are considered “equity awards,” because they may only be settled in shares. Directors immediately vest in units issued to them. The fair value of the units is determined using the closing price of Con Edison’s common stock on the business day immediately preceding the date of issue. In the year ended December 31, 2016 , approximately 27,600 units were issued at a weighted average grant date price of $74.37 . Stock Purchase Plan The Stock Purchase Plan, which was approved by shareholders in 2004 and 2014, provides for the Companies to contribute up to $1 for each $9 invested by their directors, officers or employees to purchase Con Edison common stock under the plan. Eligible participants may invest up to $25,000 during any calendar year (subject to an additional limitation for officers and employees of not more than 20 percent of their pay). Dividends paid on shares held under the plan are reinvested in additional shares unless otherwise directed by the participant. Participants in the plan immediately vest in shares purchased by them under the plan. The fair value of the shares of Con Edison common stock purchased under the plan was calculated using the average of the high and low composite sale prices at which shares were traded at the New York Stock Exchange on the trading day immediately preceding such purchase dates. During 2016 , 2015 and 2014 , 720,268 , 761,784 and 708,276 shares were purchased under the Stock Purchase Plan at a weighted average price of $72.67 , $62.75 and $56.23 per share, respectively.

Financial Information by Busine

Financial Information by Business Segment	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Financial Information by Business Segment	Financial Information by Business Segment The business segments of each of the Companies, which are its operating segments, were determined based on management’s reporting and decision-making requirements in accordance with the accounting rules for segment reporting. Con Edison’s principal business segments are CECONY’s regulated utility activities, O&R’s regulated utility activities, the Clean Energy Businesses and Con Edison Transmission. CECONY’s principal business segments are its regulated electric, gas and steam utility activities. Con Edison Transmission, which had begun investing in electric transmission and gas pipeline and storage assets (see Note U), was added in June 2016 as a separate reportable segment based on management’s reporting and decision-making, including performance evaluation and resource allocation. For comparison purposes, the previously reported financial information by business segments was reclassified to reflect the current business segment presentation. All revenues of these business segments are from customers located in the United States of America. Also, all assets of the business segments are located in the United States of America. The accounting policies of the segments are the same as those described in Note A. Common services shared by the business segments are assigned directly or allocated based on various cost factors, depending on the nature of the service provided. The financial data for the business segments are as follows: As of and for the Year Ended December 31, 2016 (Millions of Dollars) Operating revenues Inter- segment revenues Depreciation and amortization Operating income Other Income (deductions) Interest charges Income taxes on operating income (a) Total assets Capital expenditures CECONY Electric $8,106 $17 $865 $1,847 $2 $459 $495 $30,708 $1,819 Gas 1,508 6 159 357 (1) 105 92 7,553 811 Steam 551 88 82 58 (1) 39 30 2,595 126 Consolidation adjustments — (111) — — — — — — — Total CECONY $10,165 $— $1,106 $2,262 $— $603 $617 $40,856 $2,756 O&R Electric $637 $— $49 $95 $1 $24 $30 $1,949 $114 Gas 184 — 18 35 — 12 10 809 52 Other — — — — — — — — — Total O&R $821 $— $67 $130 $1 $36 $40 $2,758 $166 Clean Energy Businesses $1,091 $7 $42 $183 $21 $34 $53 $2,551 $1,235 Con Edison Transmission — — — (3) 43 6 — 1,150 1,078 Other (b) (2) (7) 1 3 (1) 17 4 940 — Total Con Edison $12,075 $— $1,216 $2,575 $64 $696 $714 $48,255 $5,235 As of and for the Year Ended December 31, 2015 (Millions of Dollars) Operating revenues Inter- segment revenues Depreciation and amortization Operating income Other Income (deductions) Interest charges Income taxes on operating income (a) Total assets (c) Capital expenditures CECONY Electric $8,172 $18 $820 $1,798 $(2) $447 $447 $30,603 $1,658 Gas 1,527 6 142 356 (2) 96 100 6,974 671 Steam 629 86 78 93 (1) 41 41 2,653 106 Consolidation adjustments — (110) — — — — — — — Total CECONY $10,328 $— $1,040 $2,247 $(5) $584 $588 $40,230 $2,435 O&R Electric $663 $— $50 $103 $(2) $23 $31 $2,140 $114 Gas 182 — 18 18 (2) 12 2 579 46 Other — — — — — — — — — Total O&R $845 $— $68 $121 $(4) $35 $33 $2,719 $160 Clean Energy Businesses $1,383 $(2) $22 $58 $35 $11 $22 $1,680 $823 Con Edison Transmission — — — — — — — 3 — Other (b) (2) 2 — 1 (2) 23 1 1,010 — Total Con Edison $12,554 $— $1,130 $2,427 $24 $653 $644 $45,642 $3,418 As of and for the Year Ended December 31, 2014 (Millions of Dollars) Operating revenues Inter- segment revenues Depreciation and amortization Operating income Other Income (deductions) Interest charges Income taxes on operating income (a) Total assets (c) Capital expenditures CECONY Electric $8,437 $16 $781 $1,712 $8 $412 $425 $30,295 $1,500 Gas 1,721 6 132 314 2 89 88 6,478 549 Steam 628 84 78 113 1 36 49 2,670 83 Consolidation adjustments — (106) — — — — — — — Total CECONY $10,786 $— $991 $2,139 $11 $537 $562 $39,443 $2,132 O&R Electric $680 $— $46 $103 $3 $24 $29 $2,023 $105 Gas 212 — 15 25 — 10 6 786 37 Other — — — — — 1 — 1 — Total O&R $892 $— $61 $128 $3 $35 $35 $2,810 $142 Clean Energy Businesses $1,244 $(10) $19 $(60) $28 $(8) $(8) $1,013 $447 Con Edison Transmission — — — — — — — 1 — Other (b) (3) 10 — 2 — 27 — 804 — Total Con Edison $12,919 $— $1,071 $2,209 $42 $591 $589 $44,071 $2,721 (a) For Con Edison, the income tax expense on non-operating income was $16 million , $40 million and $21 million in 2016 , 2015 and 2014 , respectively. For CECONY, the income tax expense on non-operating income was $14 million , $14 million and $7 million in 2016 , 2015 and 2014 , respectively. (b) Parent company and consolidation adjustments. Other does not represent a business segment. (c) Reflects $237 million in 2014, related to the adoption of ASU No. 2015-03, “Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs” and ASU No. 2015-17, “Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes.” See Notes C and L.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities Commodity Derivatives Con Edison’s subsidiaries hedge market price fluctuations associated with physical purchases and sales of electricity, natural gas, steam and, to a lesser extent, refined fuels by using derivative instruments including futures, forwards, basis swaps, options, transmission congestion contracts and financial transmission rights contracts. Derivatives are recognized on the consolidated balance sheet at fair value (see Note P), unless an exception is available under the accounting rules for derivatives and hedging. Qualifying derivative contracts that have been designated as normal purchases or normal sales contracts are not reported at fair value under the accounting rules. The fair values of the Companies’ commodity derivatives including the offsetting of assets and liabilities on the consolidated balance sheet at December 31, 2016 and 2015 were: (Millions of Dollars) 2016 2015 Balance Sheet Location Gross Amounts of Recognized Assets/ (Liabilities) Gross Amounts Offset Net Amounts of Assets/(Liabilities) (a) Gross Amounts of Recognized Assets/ (Liabilities) Gross Amounts Offset Net Amounts of Assets/(Liabilities) (a) Con Edison Fair value of derivative assets Current $81 $(64) $17 (b) $59 $(41) $18 (b) Current - assets held for sale (c) — — — 51 (50) 1 Noncurrent 49 (43) 6 57 (54) 3 Noncurrent - assets held for sale (c) — — — 15 (15) — Total fair value of derivative assets $130 $(107) $23 $182 $(160) $22 Fair value of derivative liabilities Current $(138) $61 $(77) $(144) $78 $(66) Current - liabilities held for sale (c) — — — (115) 50 (65) Noncurrent (91) 52 (39) (d) (102) 63 (39) Noncurrent - liabilities held for sale (c) — — — (28) 15 (13) Total fair value of derivative liabilities $(229) $113 $(116) $(389) $206 $(183) Net fair value derivative assets/(liabilities) $(99) $6 $(93) (b)(d) $(207) $46 $(161) (b) CECONY Fair value of derivative assets Current $52 $(45) $7 (b) $40 $(32) $8 (b) Noncurrent 41 (35) 6 48 (47) 1 Total fair value of derivative assets $93 $(80) $13 $88 $(79) $9 Fair value of derivative liabilities Current $(111) $45 $(66) $(121) $71 $(50) Noncurrent (77) 44 (33) (92) 56 (36) Total fair value of derivative liabilities $(188) $89 $(99) $(213) $127 $(86) Net fair value derivative assets/(liabilities) $(95) $9 $(86) (b) $(125) $48 $(77) (b) (a) Derivative instruments and collateral were offset on the consolidated balance sheet as applicable under the accounting rules. The Companies enter into master agreements for their commodity derivatives. These agreements typically provide offset in the event of contract termination. In such case, generally the non-defaulting party’s payable will be offset by the defaulting party’s payable. The non-defaulting party will customarily notify the defaulting party within a specific time period and come to an agreement on the early termination amount. (b) At December 31, 2016 and 2015 , margin deposits for Con Edison ( $7 million and $26 million , respectively) and CECONY ( $7 million and $26 million , respectively) were classified as derivative assets on the consolidated balance sheet, but not included in the table. Margin is collateral, typically cash, that the holder of a derivative instrument is required to deposit in order to transact on an exchange and to cover its potential losses with its broker or the exchange. (c) Amounts represent derivative assets and liabilities included in assets and liabilities held for sale on the consolidated balance sheet. (d) Does not include ($1) million for interest rate swap (see below). The Utilities generally recover their prudently incurred fuel, purchased power and gas costs, including hedging gains and losses, in accordance with rate provisions approved by the applicable state utility regulators. See "Recoverable Energy Costs" in Note A. In accordance with the accounting rules for regulated operations, the Utilities record a regulatory asset or liability to defer recognition of unrealized gains and losses on their electric and gas derivatives. As gains and losses are realized in future periods, they will be recognized as purchased power, gas and fuel costs in the Companies’ consolidated income statements. The Clean Energy Businesses record realized and unrealized gains and losses on their derivative contracts in purchased power, gas purchased for resale and non-utility revenue in the reporting period in which they occur. Management believes that these derivative instruments represent economic hedges that mitigate exposure to fluctuations in commodity prices. The following table presents the realized and unrealized gains or losses on commodity derivatives that have been deferred or recognized in earnings for the years ended December 31, 2016 and 2015 : Con Edison CECONY (Millions of Dollars) Balance Sheet Location 2016 2015 2016 2015 Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: Current Deferred derivative gains $23 $1 $18 $2 Noncurrent Deferred derivative gains 1 1 2 — Total deferred gains/(losses) $24 $2 $20 $2 Current Deferred derivative losses $22 $(16) $18 $(11) Current Recoverable energy costs (212) (136) (194) (127) Noncurrent Deferred derivative losses 2 (25) 4 (23) Total deferred gains/(losses) $(188) $(177) $(172) $(161) Net deferred gains/(losses) $(164) $(175) $(152) $(159) Income Statement Location Pre-tax gain/(loss) recognized in income Purchased power expense $(101) (a) $(109) (b) $— $— Gas purchased for resale (112) (106) — — Non-utility revenue 9 (a) 30 (b) — — Other operations and maintenance expense 1 (c) (1) (d) 1 (c) (1) (d) Total pre-tax gain/(loss) recognized in income $(203) $(186) $1 $(1) (a) For the year ended December 31, 2016 , Con Edison recorded unrealized pre-tax gains and losses in non-utility operating revenue ( $5 million loss) and purchased power expense ( $11 million gain). (b) For the year ended December 31, 2015 , Con Edison recorded unrealized pre-tax gains and losses in non-utility operating revenue ( $1 million gain) and purchased power expense ( $1 million loss). (c) For the year ended December 31, 2016 , Con Edison and CECONY recorded an unrealized gain in other operations and maintenance expense ( $1 million ). (d) For the year ended December 31, 2015 , Con Edison and CECONY recorded an unrealized loss in other operations and maintenance expense ( $1 million ). The following table presents the hedged volume of Con Edison’s and CECONY’s derivative transactions at December 31, 2016 : Electric Energy (MWh) (a)(b) Capacity (MW) (a) Natural Gas (Dt) (a)(b) Refined Fuels (gallons) Con Edison 21,235,830 13,616 77,248,786 3,696,000 CECONY 19,258,400 7,500 71,060,000 3,696,000 (a) Volumes are reported net of long and short positions, except natural gas collars where the volumes of long positions are reported. (b) Excludes electric congestion and gas basis swap contracts which are associated with electric and gas contracts and hedged volumes. The Companies are exposed to credit risk related to transactions entered into primarily for the various energy supply and hedging activities by the Utilities and the Clean Energy Businesses. Credit risk relates to the loss that may result from a counterparty’s nonperformance. The Companies use credit policies to manage this risk, including an established credit approval process, monitoring of counterparty limits, netting provisions within agreements, collateral or prepayment arrangements, credit insurance and credit default swaps. The Companies measure credit risk exposure as the replacement cost for open energy commodity and derivative positions plus amounts owed from counterparties for settled transactions. The replacement cost of open positions represents unrealized gains, net of any unrealized losses where the Companies have a legally enforceable right to offset. At December 31, 2016 , Con Edison and CECONY had $62 million and $20 million of credit exposure in connection with energy supply and hedging activities, net of collateral, respectively. Con Edison’s net credit exposure consisted of $25 million with commodity exchange brokers, $17 million with investment-grade counterparties, $11 million with non-investment grade/non-rated counterparties and $9 million with independent system operators. CECONY’s net credit exposure consisted of $14 million with commodity exchange brokers and $6 million with investment-grade counterparties. The collateral requirements associated with, and settlement of, derivative transactions are included in net cash flows from operating activities in the Companies’ consolidated statement of cash flows. Most derivative instrument contracts contain provisions that may require a party to provide collateral on its derivative instruments that are in a net liability position. The amount of collateral to be provided will depend on the fair value of the derivative instruments and the party’s credit ratings. The following table presents the aggregate fair value of the Companies’ derivative instruments with credit-risk-related contingent features that are in a net liability position, the collateral posted for such positions and the additional collateral that would have been required to be posted had the lowest applicable credit rating been reduced one level and to below investment grade at December 31, 2016 : (Millions of Dollars) Con Edison (a) CECONY (a) Aggregate fair value – net liabilities $113 $103 Collateral posted 43 42 Additional collateral (b) (downgrade one level from current ratings) 11 10 Additional collateral (b)(c) (downgrade to below investment grade from current ratings) 75 65 (a) Non-derivative transactions for the purchase and sale of electricity and gas and qualifying derivative instruments, which have been designated as normal purchases or normal sales, are excluded from the table. These transactions primarily include purchases of electricity from independent system operators. In the event the Utilities and the Clean Energy Businesses were no longer extended unsecured credit for such purchases, the Companies would be required to post additional collateral of $43 million at December 31, 2016 . For certain other such non-derivative transactions, the Companies could be required to post collateral under certain circumstances, including in the event counterparties had reasonable grounds for insecurity. (b) The Companies measure the collateral requirements by taking into consideration the fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liabilities position plus amounts owed to counterparties for settled transactions and amounts required by counterparties for minimum financial security. The fair value amounts represent unrealized losses, net of any unrealized gains where the Companies have a legally enforceable right to offset. (c) Derivative instruments that are net assets have been excluded from the table. At December 31, 2016 , if Con Edison had been downgraded to below investment grade, it would have been required to post additional collateral for such derivative instruments of $15 million . Interest Rate Swap In December 2016, the Clean Energy Businesses acquired Coram Wind (see Note U) which holds an interest rate swap that terminates in June 2024, pursuant to which it pays a fixed-rate of 2.0855 percent and receives a LIBOR-based variable rate. The fair value of this interest rate swap at the time of acquisition was a liability of $1 million which was added to Con Edison’s consolidated balance sheet. Subsequent changes to the fair value after the date of acquisition are recorded in the company’s consolidated income statement as other interest expense and were immaterial for the year ended December 31, 2016.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The accounting rules for fair value measurements and disclosures define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in a principal or most advantageous market. Fair value is a market-based measurement that is determined based on inputs, which refer broadly to assumptions that market participants use in pricing assets or liabilities. These inputs can be readily observable, market corroborated, or generally unobservable firm inputs. The Companies often make certain assumptions that market participants would use in pricing the asset or liability, including assumptions about risk, and the risks inherent in the inputs to valuation techniques. The Companies use valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. The accounting rules for fair value measurements and disclosures established a fair value hierarchy, which prioritizes the inputs to valuation techniques used to measure fair value in three broad levels. The rules require that assets and liabilities be classified in their entirety based on the level of input that is significant to the fair value measurement. Assessing the significance of a particular input may require judgment considering factors specific to the asset or liability, and may affect the valuation of the asset or liability and their placement within the fair value hierarchy. The Companies classify fair value balances based on the fair value hierarchy defined by the accounting rules for fair value measurements and disclosures as follows: • Level 1 – Consists of assets or liabilities whose value is based on unadjusted quoted prices in active markets at the measurement date. An active market is one in which transactions for assets or liabilities occur with sufficient frequency and volume to provide pricing information on an ongoing basis. This category includes contracts traded on active exchange markets valued using unadjusted prices quoted directly from the exchange. • Level 2 – Consists of assets or liabilities valued using industry standard models and based on prices, other than quoted prices within Level 1, that are either directly or indirectly observable as of the measurement date. The industry standard models consider observable assumptions including time value, volatility factors and current market and contractual prices for the underlying commodities, in addition to other economic measures. This category includes contracts traded on active exchanges or in over-the-counter markets priced with industry standard models. • Level 3 – Consists of assets or liabilities whose fair value is estimated based on internally developed models or methodologies using inputs that are generally less readily observable and supported by little, if any, market activity at the measurement date. Unobservable inputs are developed based on the best available information and subject to cost benefit constraints. This category includes contracts priced using models that are internally developed and contracts placed in illiquid markets. It also includes contracts that expire after the period of time for which quoted prices are available and internal models are used to determine a significant portion of the value. Assets and liabilities measured at fair value on a recurring basis for the years ended December 31, 2016 and 2015 are summarized below. 2016 2015 (Millions of Dollars) Level 1 Level 2 Level 3 Netting Adjustment (e) Total Level 1 Level 2 Level 3 Netting Adjustment (e) Total Con Edison Derivative assets: Commodity (a)(b)(c) $14 $33 $7 $(24) $30 $2 $25 $13 $7 $47 Commodity held for sale (f) — — — — — — 63 1 (63) 1 Other (a)(b)(d) 222 111 — — 333 185 112 — — 297 Total assets $236 $144 $7 $(24) $363 $187 $200 $14 $(56) $345 Derivative liabilities: Commodity (a)(b)(c) $4 $144 $6 $(38) $116 $16 $153 $1 $(65) $105 Interest Rate Swap (a)(b)(c)(g) — 1 — — 1 — — — — — Commodity held for sale (f) — — — — — 1 133 7 (63) 78 Total liabilities $4 $145 $6 $(38) $117 $17 $286 $8 $(128) $183 CECONY Derivative assets: Commodity (a)(b)(c) $10 $19 $1 $(10) $20 $1 $9 $8 $17 $35 Other (a)(b)(d) 200 106 — — 306 171 105 — — 276 Total assets $210 $125 $1 $(10) $326 $172 $114 $8 $17 $311 Derivative liabilities: Commodity (a)(b)(c) $1 $124 $— $(26) $99 $14 $129 $— $(57) $86 (a) The Companies’ policy is to review the fair value hierarchy and recognize transfers into and transfers out of the levels at the end of each reporting period. There were no transfers between levels 1 , 2 and 3 for the years ended December 31, 2016 and 2015 . (b) Level 2 assets and liabilities include investments held in the deferred compensation plan and/or non-qualified retirement plans, interest rate swap, exchange-traded contracts where there is insufficient market liquidity to warrant inclusion in Level 1, certain over-the-counter derivative instruments for electricity, refined products and natural gas. Derivative instruments classified as Level 2 are valued using industry standard models that incorporate corroborated observable inputs; such as pricing services or prices from similar instruments that trade in liquid markets, time value and volatility factors. (c) The accounting rules for fair value measurements and disclosures require consideration of the impact of nonperformance risk (including credit risk) from a market participant perspective in the measurement of the fair value of assets and liabilities. At December 31, 2016 and 2015 , the Companies determined that nonperformance risk would have no material impact on their financial position or results of operations. (d) Other assets are comprised of assets such as life insurance contracts within the deferred compensation plan and non-qualified retirement plans. (e) Amounts represent the impact of legally-enforceable master netting agreements that allow the Companies to net gain and loss positions and cash collateral held or placed with the same counterparties. (f) Amounts represent derivative assets and liabilities included in Assets and Liabilities held for sale on the consolidated balance sheet (see Note U). (g) See Note O. The employees in the Companies’ risk management group develop and maintain the Companies’ valuation policies and procedures for, and verify pricing and fair value valuation of, commodity derivatives. Under the Companies’ policies and procedures, multiple independent sources of information are obtained for forward price curves used to value commodity derivatives. Fair value and changes in fair value of commodity derivatives are reported on a monthly basis to the Companies’ risk committees, comprised of officers and employees of the Companies that oversee energy hedging at the Utilities and the Clean Energy Businesses. The risk management group reports to the Companies’ Vice President and Treasurer. Fair Value of Level 3 at December 31, 2016 (Millions of Dollars) Valuation Techniques Unobservable Inputs Range Con Edison — Commodity Electricity $(1) Discounted Cash Flow Forward energy prices (a) $37.75-$55.00 per MWh Discounted Cash Flow Forward capacity prices (a) $2.42-$10.25 per kW-month Transmission Congestion Contracts/Financial Transmission Rights 2 Discounted Cash Flow Discount to adjust auction prices for inter-zonal forward price curves (b) 50.0% Discount/(premium) to adjust auction prices for historical monthly realized settlements (b) (75.2)%-58.9% Inter-zonal forward price curves adjusted for historical zonal losses (b) $1.11-$2.90 per MWh Total Con Edison — Commodity $1 CECONY — Commodity Transmission Congestion Contracts $1 Discounted Cash Flow Discount to adjust auction prices for inter-zonal forward price curves (b) 50.0% Discount/(premium) to adjust auction prices for historical monthly realized settlements (b) (75.2)%-58.9% (a) Generally, increases/(decreases) in this input in isolation would result in a higher/(lower) fair value measurement. (b) Generally, increases/(decreases) in this input in isolation would result in a lower/(higher) fair value measurement. The table listed below provides a reconciliation of the beginning and ending net balances for assets and liabilities measured at fair value for the years ended December 31, 2016 and 2015 and classified as Level 3 in the fair value hierarchy: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Beginning balance as of January 1, $6 $20 $8 $13 Included in earnings (7) (20) (1) (6) Included in regulatory assets and liabilities (6) 1 (6) — Purchases 4 11 2 5 Sales (a) 4 — — — Settlements — (6) (2) (4) Ending balance as of December 31, $1 $6 $1 $8 (a) Amounts represent derivative instruments novated as part of the assets of Con Edison Solutions’ retail electric supply business which were sold to a subsidiary of Exelon Corporation (see Note U). For the Utilities, realized gains and losses on Level 3 commodity derivative assets and liabilities are reported as part of purchased power, gas and fuel costs. The Utilities generally recover these costs in accordance with rate provisions approved by the applicable state public utilities regulators. See Note A. Unrealized gains and losses for commodity derivatives are generally deferred on the consolidated balance sheet in accordance with the accounting rules for regulated operations. For the Clean Energy Businesses, realized and unrealized gains and losses on Level 3 commodity derivative assets and liabilities are reported in non-utility revenues ( immaterial for both years) and purchased power costs ( $6 million loss and $14 million loss) on the consolidated income statement for the years ended December 31, 2016 and 2015 , respectively. The change in fair value relating to Level 3 commodity derivative assets and liabilities held at December 31, 2016 and 2015 is included in non-utility revenues (immaterial for both years) and purchased power costs ( $1 million loss and $8 million loss) on the consolidated income statement for the years ended December 31, 2016 and 2015 , respectively.

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Variable Interest Entities	Variable Interest Entities The accounting rules for consolidation address the consolidation of a variable interest entity (VIE) by a business enterprise that is the primary beneficiary. A VIE is an entity that does not have a sufficient equity investment at risk to permit it to finance its activities without additional subordinated financial support, or whose equity investors lack the characteristics of a controlling financial interest. The primary beneficiary is the business enterprise that has the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and either absorbs a significant amount of the VIE’s losses or has the right to receive benefits that could be significant to the VIE. Con Edison enters into arrangements including leases, partnerships and electricity purchase agreements, with various entities. As a result of these arrangements, Con Edison retains or may retain a variable interest in these entities. CECONY CECONY had a variable interest in a non-consolidated VIE, Astoria Energy, LLC (Astoria Energy), with which CECONY entered into a long-term electricity purchase agreement that expired in April 2016. CECONY has ongoing long-term electricity purchase agreements with the following two potential VIEs: Cogen Technologies Linden Venture, LP and Brooklyn Navy Yard Cogeneration Partners, LP. In 2016 , requests were made of these counterparties for information necessary to determine whether the entity was a VIE and whether CECONY is the primary beneficiary; however, the information was not made available. See Note I for information on these electricity purchase agreements, the payments pursuant to which constitute CECONY's maximum exposure to loss with respect to the potential VIEs. Con Edison Development Con Edison has a variable interest in OCI Solar San Antonio 4 LLC (Texas Solar 4), which is a consolidated entity in which Con Edison Development has an 80 percent membership interest. Con Edison is the primary beneficiary since the power to direct the activities that most significantly impact the economics of Texas Solar 4 is held by Con Edison Development. Texas Solar 4 owns a project company that developed a 40 MW (AC) solar electric production project in Texas. Electricity generated by the project is sold to the City of San Antonio pursuant to a long-term power purchase agreement. At December 31, 2016 and 2015 , Con Edison’s consolidated balance sheet includes $54 million and $58 million in net assets (as detailed in the table below) and the noncontrolling interest of the third party of $7 million and $9 million related to Texas Solar 4, respectively. Earnings for the year ended December 31, 2016 and 2015 were immaterial. (Millions of Dollars) 2016 2015 Restricted cash $8 $9 Receivable from parent company 35 32 Non-utility property, less accumulated depreciation of $9 and $5, respectively 104 107 Other assets 8 11 Total assets (a) $155 $159 Long-term debt due within one year $3 $2 Other liabilities 38 37 Long-term debt 60 62 Total liabilities (b) $101 $101 (a) The assets of Texas Solar 4 represent assets of a consolidated VIE that can be used only to settle obligations of the consolidated VIE. (b) The liabilities of Texas Solar 4 represent liabilities of a consolidated VIE for which creditors do not have recourse to the general credit of the primary beneficiary. The following table summarizes the VIEs in which Con Edison Development has entered into as of December 31, 2016 : Project Name (a) Generating Capacity (b) (MW AC) Power Purchase Agreement Term in Years Year of Initial Investment Location Maximum Millions of Dollars ) (c) Copper Mountain Solar 3 128 20 2014 Nevada $179 Mesquite Solar 1 83 20 2013 Arizona 108 Copper Mountain Solar 2 75 25 2013 Nevada 84 California Solar 55 25 2012 California 69 Broken Bow II 38 25 2014 Nebraska 48 Texas Solar 4 32 25 2014 Texas 47 (a) With the exception of Texas Solar 4, Con Edison’s ownership interest is 50 percent and these projects are accounted for using the equity method of accounting. With the exception of Texas Solar 4, Con Edison is not the primary beneficiary since the power to direct the activities that most significantly impact the economics of the entities are shared equally between Con Edison Development and third parties. Con Edison’s ownership interest in Texas Solar 4 is 80 percent and is consolidated in the financial statements. Con Edison is the primary beneficiary since the power to direct the activities that most significantly impact the economics of Texas Solar 4 is held by Con Edison Development. (b) Represents Con Edison Development’s ownership interest in the project. (c) For investments accounted for under the equity method, maximum exposure is equal to the carrying value of the investment on the consolidated balance sheet. For consolidated investments, such as Texas Solar 4, maximum exposure is equal to the net assets of the project on the consolidated balance sheet less any applicable noncontrolling interest ( $7 million for Texas Solar 4). Con Edison did not provide any financial or other support during the year that was not previously contractually required.

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2016
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations The Companies recognize a liability at fair value for legal obligations associated with the retirement of long-lived assets in the period in which they are incurred, or when sufficient information becomes available to reasonably estimate the fair value of such legal obligations. When the liability is initially recorded, asset retirement costs are capitalized by increasing the carrying amount of the related asset. The liability is accreted to its present value each period and the capitalized cost is depreciated over the useful life of the related asset. The fair value of the asset retirement obligation liability is measured using expected future cash flows discounted at credit-adjusted risk-free rates, historical information, and where available, quoted prices from outside contractors. The Companies evaluate these assumptions underlying the asset retirement obligation liability on an annual basis or as frequently as needed. The Companies recorded asset retirement obligations associated with the removal of asbestos and asbestos-containing material in their buildings (other than the structures enclosing generating stations and substations), electric equipment and steam and gas distribution systems. The Companies also recorded asset retirement obligations relating to gas and oil pipelines abandoned in place. The Companies did not record an asset retirement obligation for the removal of asbestos associated with the structures enclosing generating stations and substations. For these building structures, the Companies were unable to reasonably estimate their asset retirement obligations because the Companies were unable to estimate the undiscounted retirement costs or the retirement dates and settlement dates. The amount of the undiscounted retirement costs could vary considerably depending on the disposition method for the building structures, and the method has not been determined. The Companies anticipate continuing to use these building structures in their businesses for an indefinite period, and so the retirement dates and settlement dates are not determinable. Con Edison recorded asset retirement obligations for the removal of the Clean Energy Businesses’ solar and wind equipment related to projects located on property that is not owned by them and the term of the arrangement is finite including any renewal options. Con Edison did not record asset retirement obligations for the Clean Energy Businesses’ projects that are located on property that is owned by them because they expect that the equipment will continue to generate electricity at these facilities long past the manufacturer’s warranty at minimal operating expense. Therefore, Con Edison was unable to reasonably estimate the retirement date of this equipment. The Utilities include in depreciation rates the estimated removal costs, less salvage, for utility plant assets. The amounts related to removal costs that are associated with asset retirement obligations are classified as an asset retirement liability. Pursuant to accounting rules for regulated operations, future removal costs that do not represent legal asset retirement obligations are recorded as regulatory liabilities. Accretion and depreciation expenses related to removal costs that represent legal asset retirement obligations are applied against the Companies’ regulatory liabilities. Asset retirement costs that are recoverable from customers are recorded as regulatory liabilities to reflect the timing difference between costs recovered through the rate-making process and recognition of costs. At December 31, 2016 , the liabilities for asset retirement obligations of Con Edison and CECONY were $246 million and $227 million , respectively. At December 31, 2015 , the liabilities for asset retirement obligations of Con Edison and CECONY were $242 million and $234 million , respectively. The change in liabilities at December 31, 2016 was due to changes in estimated cash flows of $29 million and $19 million for Con Edison and CECONY, respectively, and accretion expense of $10 million and $9 million for Con Edison and CECONY, respectively. The changes were offset by liabilities settled of $35 million for both Con Edison and CECONY. Con Edison and CECONY also recorded reductions of $37 million and $23 million during the years ended December 31, 2016 and 2015 , respectively, to the regulatory liability associated with cost of removal to reflect depreciation and interest expense.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The Utilities and the Clean Energy Businesses provide administrative and other services to each other pursuant to cost allocation procedures approved by the NYSPSC. The costs of administrative and other services provided by CECONY to, and received by it from, Con Edison and its other subsidiaries for the years ended December 31, 2016 , 2015 and 2014 were as follows: CECONY (Millions of Dollars) 2016 2015 2014 Cost of services provided $108 $99 $90 Cost of services received 64 60 57 In addition, CECONY and O&R have joint gas supply arrangements, in connection with which CECONY sold to O&R $47 million , $54 million and $80 million of natural gas for the years ended December 31, 2016 , 2015 and 2014 , respectively. These amounts are net of the effect of related hedging transactions. The Utilities perform work and incur expenses on behalf of NY Transco, a company in which CET Electric has a 45.7 percent equity interest. The Utilities bill NY Transco for such work and expenses in accordance with established policies. For the year ended December 31, 2016, the amounts billed by the Utilities to NY Transco were immaterial. In May 2016, CECONY transferred certain electric transmission projects to NY Transco (see Note U). CECONY has storage and wheeling service contracts with Stagecoach Gas Services LLC (Stagecoach), a joint venture formed by a subsidiary of CET Gas and a subsidiary of Crestwood Equity Partners LP (Crestwood) (see Note U). In addition, CECONY is the replacement shipper on one of Crestwood’s firm transportation agreements with Tennessee Gas Pipeline Company LLC. From the inception of the joint venture in June 2016 through December 31, 2016 , the amount of storage and wheeling services received by CECONY from Stagecoach was $18 million . In addition, the Clean Energy Businesses entered into two electricity sales agreements with Stagecoach under which the amounts received in 2016 were immaterial. CECONY has a financial electric capacity contract with Con Edison Energy for the period May 2016 through April 2017. For the year ended December 31, 2016, Con Edison Energy's realized gains under this contract were immaterial. FERC has authorized CECONY through 2017 to lend funds to O&R from time to time, for periods of not more than 12 months , in amounts not to exceed $250 million outstanding at any time, at prevailing market rates. There were no outstanding loans to O&R at December 31, 2016 and 2015 .

New Financial Accounting Standa

New Financial Accounting Standards	12 Months Ended
	Dec. 31, 2016
Accounting Changes and Error Corrections [Abstract]
New Financial Accounting Standards	New Financial Accounting Standards In May 2014, the Financial Accounting Standards Board (FASB) and the International Accounting Standards Board jointly issued a revenue recognition standard that will supersede the revenue recognition requirements within Accounting Standards Codification Topic 605, “Revenue Recognition,” and most industry-specific guidance under the Codification through Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” The purpose of the new guidance is to create a consistent framework for revenue recognition. The guidance clarifies how to measure and recognize revenue arising from customer contracts to depict the transfer of goods or services in an amount that reflects the consideration the entity expects to receive. Amendments were issued subsequently to clarify key areas including principal/agent considerations, performance obligations, licensing, sales taxes, noncash consideration, and contracts. The new standard is effective for reporting periods beginning after December 15, 2017. Early adoption is permitted for reporting periods beginning after December 15, 2016, however, the Companies plan to adopt the new standard for reporting periods beginning after December 15, 2017. Under the new standard, companies may use either of the following transition methods: (i) a full retrospective approach reflecting the application of the standard in each prior reporting period with the option to elect certain practical expedients, or (ii) a modified retrospective approach with the cumulative effect of initially adopting ASU 2014-09 recognized at the date of adoption (which includes additional footnote disclosures). The Companies anticipate using the modified retrospective approach. The Companies are currently in the process of evaluating the impact of the new standard on their various revenue streams. The majority of the Companies’ sales are derived from tariffs to provide electric, gas, and steam service to customers. For such tariffs, the Companies expect that the revenue from contracts with the customer under ASU 2014-09 will be equivalent to the electricity, gas, or steam supplied in that period which is consistent with current practice. Consequently, the Companies do not anticipate that the new standard will significantly impact the amount and/or timing of such revenues. The Companies continue to review the potential impacts of other revenue at the Utilities and the Clean Energy Businesses on the Companies' financial position, results of operations and liquidity as well as the additional disclosures required under the new standard. In January 2016, the FASB issued amendments on certain aspects of recognition, measurement, presentation, and disclosure of financial instruments through ASU No. 2016-01, “Financial Instruments (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” The amendments require changes to the accounting for equity investments, the presentation and disclosure requirements for financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, clarification was provided related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. Early adoption is permitted for portions of the standard. The Companies are in the process of evaluating the potential impact of the new guidance on the Companies’ financial position, results of operations and liquidity. In February 2016, the FASB issued amendments on financial reporting of leasing transactions through ASU No. 2016-02, “Leases (Topic 842)." The amendments require lessees to recognize assets and liabilities on the balance sheet and disclose key information about leasing arrangements. Lessees will need to recognize a right-of-use asset and a lease liability for virtually all of their leases (other than leases that meet the definition of a short-term lease). Lessor accounting is similar to the current model, but updated to align with certain changes to the lessee model. For income statement purposes, the pattern of expense recognition will be dependent on whether transactions are designated as operating leases or finance leases. The amendments are effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The amendments must be adopted using a modified retrospective transition and provide for certain practical expedients. Based on the existing portfolio of leases at implementation, for leases currently classified as operating leases, the Companies expect to recognize on the statements of financial position right-of-use assets and lease liabilities. The Companies are in the process of evaluating the potential impact of the new guidance on the Companies’ results of operations and liquidity. In March 2016, the FASB issued amendments to the guidance for Derivatives and Hedging accounting through ASU 2016-05, “Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships." The amendments clarify that a change in the counterparty to a derivative instrument that has been designated as a hedging instrument under Topic 815 does not, in and of itself, require discontinuation of the application of hedge accounting. The amendments in this update are effective for financial statements issued for reporting periods beginning after December 15, 2016. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In March 2016, the FASB issued amendments to clarify the guidance for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts through ASU No. 2016-06, “Derivatives & Hedging (Topic 815): Contingent Put and Call Options in Debt Instruments.” An entity performing the assessment under the amendments is required to assess the embedded call (put) options solely in accordance with the four-step decision sequence. The amendments are effective for financial statements issued for reporting periods beginning after December 15, 2016. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In March 2016, the FASB issued amendments to eliminate the requirement to retroactively adopt the equity method of accounting when a company increases its level of ownership or degree of influence over an investment through ASU No. 2016-07, “Investments-Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting.” The amendments require that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in Accumulated Other Comprehensive Income at the date the investment qualifies for the equity method. The amendments are effective for reporting periods beginning after December 15, 2016. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In March 2016, the FASB issued amendments to simplify several aspects of the accounting for share-based payment transactions through ASU No. 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting.” The amendments simplify areas such as income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The amendments are effective for reporting periods beginning after December 15, 2016. The company elected to early adopt this standard as permitted, and it did not have a material impact on the Companies’ financial position, results of operations and liquidity. In May 2016, the FASB issued amendments to the guidance on revenue recognition and derivatives and hedging through ASU 2016-11, “Revenue Recognition (Topic 605) and Derivatives and Hedging (Topic 815): Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting (SEC Update).” The amendment rescinds certain SEC guidance superseded by the newly issued revenue recognition and hedging guidance (ASU 2014-09 and 2014-16 respectively). The amendments will be effective upon adoption of ASU 2014-09 and 2014-16. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In June 2016, the FASB issued amendments to the guidance for recognition of credit losses for financial instruments through ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” The amendment replaces the incurred loss impairment methodology which involved delayed recognition of credit losses. As the updated guidance now requires credit losses to be recognized when expected rather than when incurred, a broader range of reasonable and supportable information must be considered in developing the credit loss estimates. This includes financial instruments that are valued at amortized cost and available for sale. For public entities, the amendments are effective for reporting periods beginning after December 15, 2019. Early adoption is permitted for reporting periods beginning after December 15, 2018. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In August 2016, the FASB issued amendments to the guidance for the Statement of Cash Flows through ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force).” The amendment specifies the classification and presentation of certain cash flow items to reduce diversity in practice. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In October 2016, the FASB issued amendments to the guidance for Income Taxes through ASU 2016-16, “Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory).” The amendment clarifies the tax treatment of intra-entity transfers of assets other than inventory. The updated guidance requires entities to recognize the income tax consequences of an intra-entity transfer of assets other than inventory when the transfer occurs. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In October 2016, the FASB issued amendments to the guidance for Consolidation through ASU 2016-17, “Consolidation (Topic 810): Interests Held through Related Parties That Are under Common Control.” The amendments in this update change how a single decision maker of a VIE will consider its indirect interests in a VIE held by related parties under common control when performing the primary beneficiary analysis. If a single decision maker and its related parties are under common control, the single decision maker must evaluate indirect interests on a proportionate basis when evaluating whether it is a primary beneficiary of the VIE. The guidance does not change the characteristics of a primary beneficiary under GAAP but has amended the considerations in the evaluation of determining the primary beneficiary of a VIE under common control. For public entities, the amendments are effective for reporting periods beginning after December 15, 2016. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In November 2016, the FASB issued amendments to the guidance for the Statement of Cash Flows through ASU 2016-18, “Update 2016-18-Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force).” The amendments in this update clarify the presentation of changes in restricted cash and restricted cash equivalents in the statement of cash flows. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In January 2017, the FASB issued amendments to the guidance for Business Combinations through ASU 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business.” The amendments in this update clarify the definition of a business and provide guidance on evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. I n January 2017, the FASB issued amendments to the guidance for the subsequent measurement of goodwill through ASU 2017-04, “Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” The amendments in this update simplify goodwill impairment testing by eliminating Step 2 of the goodwill impairment test wherein an entity has to compute the implied fair value of goodwill by performing procedures to determine the fair value of its assets and liabilities. Under the new guidance, an entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value up to the total amount of goodwill allocated to that reporting unit. For public entities, the amendments are effective for reporting periods beginning after December 15, 2019. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity.

Acquisitions, Investments and D

Acquisitions, Investments and Dispositions	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Acquisitions, Investments and Dispositions	Acquisitions, Investments and Dispositions Acquisitions and Investments Texas Solar 7 In January 2016, Con Edison Development acquired a 100 percent equity interest in a company that is the owner of a 106 MW (AC) solar electric production project in Texas (Texas Solar 7) for $227 million , as to which $218 million was recorded as non-utility construction work in progress and the remaining $9 million was recorded as other receivables. At December 31, 2016 net assets of the project were approximately $127 million , inclusive of $41 million in an intangible asset recorded as an adjustment to the purchase price allocation in December 2016. The intangible asset pertains to the value of the project's power purchase agreement, relative to current market rates, and is being amortized over the life of the agreement. The project has been financed, in part, by debt secured by the project. Electricity generated by this project is to be purchased by the City of San Antonio pursuant to a long-term power purchase agreement. The project commenced commercial operation in the third quarter of 2016. Con Edison's equity interest in Texas Solar 7 is consolidated in the financial statements. Mountain Valley Pipeline In January 2016, CET Gas acquired a 12.5 percent equity interest in Mountain Valley Pipeline, LLC (MVP), a company developing a proposed gas transmission project in West Virginia and Virginia. The company's initial contribution to MVP was $18 million . At December 31, 2016 , CET Gas' investment in MVP was $48 million . The estimated total project cost is $3,000 million to $3,500 million . Subject to FERC approval, MVP is targeting to be fully in-service during 2018. Con Edison is accounting for its equity interest in MVP as an equity method investment. NY Transco In January 2016, CECONY entered into an agreement to transfer certain electric transmission projects to NY Transco, a company in which CET Electric has a 45.7 percent equity interest. In April 2016, the NYSPSC authorized CECONY, subject to certain conditions, to transfer the projects to NY Transco. In May 2016, CECONY transferred the projects to NY Transco for a purchase price of $122 million and an $8 million payment for easement rights on certain associated property. At December 31, 2016 , CET Electric's investment in NY Transco was $51 million . Con Edison is accounting for its equity interest in NY Transco as an equity method investment. Stagecoach Gas Services In April 2016, a CET Gas subsidiary agreed with a subsidiary of Crestwood to form a joint venture to own, operate and further develop existing gas pipeline and storage businesses located in northern Pennsylvania and southern New York. The transaction was substantially completed in June 2016, and the remainder was completed in November 2016. Crestwood contributed businesses to a new entity, Stagecoach, and the CET Gas subsidiary purchased a 50 percent equity interest in Stagecoach for $974 million . At December 31, 2016 , CET Gas' investment in Stagecoach was $992 million . Con Edison is accounting for its equity interest in Stagecoach as an equity method investment. Pilesgrove In June 2016, Con Edison Development recorded an $8 million ( $5 million , net of taxes) impairment charge on its 50 percent equity interest in Pilesgrove Solar, LLC (Pilesgrove), which owns an 18 MW (AC) solar electric production project in New Jersey. In August 2016, Con Edison Development acquired the remaining 50 percent equity interest in Pilesgrove for a purchase price of approximately $16 million and recorded a bargain purchase gain of $8 million ( $5 million , net of taxes); $45 million was recorded as non-utility property and the remaining $3 million was recorded as current assets. The impairment charge and bargain purchase gain are included in Investment and other income on Con Edison’s consolidated income statement. Con Edison's equity interest in Pilesgrove is consolidated in the financial statements. At December 31, 2016 , net assets of the project were approximately $45 million . Panoche Valley In October 2016, Con Edison Development, which owned a 50 percent equity interest, acquired the remaining 50 percent equity interest in Panoche Holdings, LLC (Panoche), which is developing a 240 MW (AC) solar electric production project in California, for cash consideration of $28 million and the release of Panoche from its obligation under a $242 million note payable to Con Edison Development. At the time of acquisition, $290 million was recorded as non-utility construction work in process, $22 million was recorded as other assets and $14 million was recorded as current liabilities. The amounts recorded are subject to adjustments to the preliminary purchase price allocation. Con Edison's equity interest in Panoche is consolidated in the financial statements. At December 31, 2016 , net assets of the project were approximately $388 million . Coram Wind In December 2016, Con Edison Development acquired a 100 percent equity interest in Coram California Development, LP (Coram), which owns a 102 MW (AC) wind electric production project in California for $97 million , as to which $191 million was recorded as non-utility property, $78 million was recorded as an intangible asset, $8 million of restricted cash was recorded as other current assets, and $180 million was recorded as long term debt. The intangible asset pertains to the value of the project's power purchase agreement, relative to current market rates, and is being amortized over the life of the agreement. The amounts recorded are subject to adjustments to the preliminary purchase price allocation. The project commenced commercial operation in March 2012. Con Edison's equity interest in Coram is consolidated in the financial statements. At December 31, 2016, net assets of the project were approximately $96 million . Dispositions Pike County Light & Power Company (Pike) In October 2015, O&R entered into an agreement to sell Pike to Corning Natural Gas Holding Corporation (Corning). In August 2016, the sale was completed. O&R received cash consideration of $15 million for the sale. O&R has agreed to provide transition services to Corning for operations and customer support for a period of up to 18 months subsequent to the sale. In addition, O&R will continue to purchase and sell to Pike electric and gas commodity for three years . Pike has an option to extend the service for up to an additional three years . At September 30, 2015, O&R recorded an impairment charge of $5 million ( $3 million , net of taxes), representing the difference between the carrying amount of Pike’s assets and the estimated sales proceeds. At December 31, 2015, Pike’s total assets and liabilities held for sale were $23 million and $5 million , respectively. There were no amounts outstanding at December 31, 2016 . Con Edison Solutions' Retail Electric Supply Business In July 2016, Con Edison Solutions entered into an agreement to sell the assets of its retail electric supply business (including retail contracts, related derivative instruments, information systems, and accounts receivable) to a subsidiary of Exelon Corporation (Exelon). In September 2016, the sale was completed for cash consideration of $235 million , subject to working capital adjustments. The sale resulted in a gain of $104 million ( $56 million , net of taxes), inclusive of a $65 million ( $42 million , net of taxes) gain on derivative instruments. The tax effect of the sale includes $16 million ( $10 million , net of federal tax) of state taxes related to a change in the apportionment of state income taxes. Con Edison Solutions has agreed to provide transition services to the Exelon subsidiary for operations and customer support through the end of 2017 during which period certain guarantees or other credit support provided by Con Edison in connection with the retail electric supply business may continue in effect. See Note H. At December 31, 2015, Con Edison Solutions' total assets and liabilities held for sale were $134 million and $84 million , respectively. There were no amounts outstanding at December 31, 2016 .

Schedule I - Condensed Financia

Schedule I - Condensed Financial Information	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule I - Condensed Financial Information	Schedule I Condensed Financial Information of Consolidated Edison, Inc. (a) Condensed Statement of Income and Comprehensive Income (Parent Company Only) For the Years Ended December 31, (Millions of Dollars, except per share amounts) 2016 2015 2014 Equity in earnings of subsidiaries $1,254 $1,195 $1,101 Other income (deductions), net of taxes 32 27 19 Interest expense (41) (29) (28) Net Income $1,245 $1,193 $1,092 Comprehensive Income $1,252 $1,204 $1,072 Net Income Per Share – Basic $4.15 $4.07 $3.73 Net Income Per Share – Diluted $4.12 $4.05 $3.71 Dividends Declared Per Share $2.68 $2.60 $2.52 Average Number Of Shares Outstanding—Basic (In Millions) 300.4 293.0 292.9 Average Number Of Shares Outstanding—Diluted (In Millions) 301.9 294.4 294.0 (a) These financial statements, in which Con Edison’s subsidiaries have been included using the equity method, should be read together with its consolidated financial statements and the notes thereto appearing above. Condensed Financial Information of Consolidated Edison, Inc. (a) Condensed Statement of Cash Flows (Parent Company Only) For the Years Ended December 31, (Millions of Dollars) 2016 2015 2014 Net Income $1,245 $1,193 $1,092 Equity in earnings of subsidiaries (1,254) (1,195) (1,101) Dividends received from: CECONY 744 872 712 O&R 43 81 40 Clean Energy Businesses 10 8 8 Change in Assets: Special deposits — — 314 Income taxes receivable 87 58 (224) Other – net (152) (382) (199) Net Cash Flows from Operating Activities 723 635 642 Investing Activities Contributions to subsidiaries (691) (15) (1) Long term debt receivable from affiliated companies (900) — — Net Cash Flows Used in Investing Activities (1,591) (15) (1) Financing Activities Net proceeds of short-term debt (53) 162 101 Issuance of long-term debt 900 — — Retirement of long-term debt (2) (2) (2) Debt issuance costs (5) — — Issuance of common shares for stock plans, net of repurchases 51 1 (10) Issuance of common shares - public offering 702 — — Common stock dividends (763) (733) (739) Net Cash Flows Used in Financing Activities 830 (572) (650) Net Change for the Period (38) 48 (9) Balance at Beginning of Period 51 3 12 Balance at End of Period $13 $51 $3 (a) These financial statements, in which Con Edison’s subsidiaries have been included using the equity method, should be read together with its consolidated financial statements and the notes thereto appearing above. Condensed Financial Information of Consolidated Edison, Inc. (a) Condensed Balance Sheet (Parent Company Only) December 31, (Millions of Dollars) 2016 2015 Assets Current Assets Cash and temporary cash investments $13 $51 Special deposits 1 1 Accounts receivable – other — 4 Income taxes receivable 79 166 Accounts receivable from affiliated companies 702 517 Prepayments 24 34 Other current assets 18 17 Total Current Assets 837 790 Investments in subsidiaries 13,991 12,737 Goodwill 406 406 Deferred income tax 42 11 Long term debt receivable from affiliated companies 900 — Other noncurrent assets (b) 16 7 Total Assets $16,192 $13,951 Liabilities and Shareholders’ Equity Current Liabilities Long-term debt due within one year $2 $2 Notes payable 384 437 Accounts Payable 1 — Accounts payable to affiliated companies 288 146 Accrued taxes 7 — Other current liabilities 14 10 Total Current Liabilities 696 595 Total Liabilities 696 595 Long-term debt (b) 1,198 304 Shareholders’ Equity Common stock, including additional paid-in capital 5,887 5,062 Retained earnings 8,411 7,990 Total Shareholders’ Equity 14,298 13,052 Total Liabilities and Shareholders’ Equity $16,192 $13,951 (a) These financial statements, in which Con Edison’s subsidiaries have been included using the equity method, should be read together with its consolidated financial statements and the notes thereto appearing above.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2016
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	Schedule II Valuation and Qualifying Accounts For the Years Ended December 31, 2016 , 2015 and 2014 COLUMN C Additions Company (Millions of Dollars) COLUMN A Description COLUMN B Balance at Beginning of Period (1) Charged To Costs And Expenses (2) Charged To Other Accounts COLUMN D Deductions(b) COLUMN E Balance At End of Period Con Edison Allowance for uncollectible accounts (a): 2016 $96 $63 $— $76 $83 2015 $106 $77 — $87 $96 2014 $103 $98 — $95 $106 CECONY Allowance for uncollectible accounts (a): 2016 $91 $57 $— $70 $78 2015 $98 $69 — $76 $91 2014 $95 $91 — $88 $98 (a) This is a valuation account deducted in the balance sheet from the assets (Accounts receivable - customers and Other receivables) to which they apply. (b) Accounts written off less cash collections, miscellaneous adjustments and amounts reinstated as receivables previously written off.

Summary of Significant Accoun34

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The Companies’ consolidated financial statements include the accounts of their respective majority-owned subsidiaries, and variable interest entities (see Note Q), as required. All intercompany balances and transactions have been eliminated.
Accounting Policies	Accounting Policies The accounting policies of Con Edison and its subsidiaries conform to generally accepted accounting principles in the United States of America (GAAP). For the Utilities, these accounting principles include the accounting rules for regulated operations and the accounting requirements of the Federal Energy Regulatory Commission (FERC) and the state regulators having jurisdiction. The accounting rules for regulated operations specify the economic effects that result from the causal relationship of costs and revenues in the rate-regulated environment and how these effects are to be accounted for by a regulated enterprise. Revenues intended to cover some costs may be recorded either before or after the costs are incurred. If regulation provides assurance that incurred costs will be recovered in the future, these costs would be recorded as deferred charges or “regulatory assets” under the accounting rules for regulated operations. If revenues are recorded for costs that are expected to be incurred in the future, these revenues would be recorded as deferred credits or “regulatory liabilities” under the accounting rules for regulated operations. The Utilities’ principal regulatory assets and liabilities are detailed in Note B. The Utilities are receiving or being credited with a return on all of their regulatory assets for which a cash outflow has been made, and are paying or being charged with a return on all of their regulatory liabilities for which a cash inflow has been received. The Utilities’ regulatory assets and liabilities will be recovered from customers, or applied for customer benefit, in accordance with rate provisions approved by the applicable state regulators.
Plant and Depreciation and Non-Utility Plant	Plant and Depreciation Utility Plant Utility plant is stated at original cost. The cost of repairs and maintenance is charged to expense and the cost of betterments is capitalized. The capitalized cost of additions to utility plant includes indirect costs such as engineering, supervision, payroll taxes, pensions, other benefits and an allowance for funds used during construction (AFUDC). The original cost of property is charged to expense over the estimated useful lives of the assets. Upon retirement, the original cost of property is charged to accumulated depreciation. See Note R. Rates used for AFUDC include the cost of borrowed funds and a reasonable rate of return on the Utilities’ own funds when so used, determined in accordance with regulations of the FERC or the state public utility regulatory authority having jurisdiction. The rate is compounded semiannually, and the amounts applicable to borrowed funds are treated as a reduction of interest charges, while the amounts applicable to the Utilities’ own funds are credited to other income (deductions). The AFUDC rates for CECONY were 4.7 percent , 4.4 percent and 1.6 percent for 2016 , 2015 and 2014 , respectively. The AFUDC rates for O&R were 3.5 percent , 0.4 percent and 2.6 percent for 2016 , 2015 and 2014 , respectively. The Utilities generally compute annual charges for depreciation using the straight-line method for financial statement purposes, with rates based on average service lives and net salvage factors. The average depreciation rates for CECONY were 3.1 percent for 2016 , 2015 and 2014 . The average depreciation rates for O&R were 2.9 percent , 3.0 percent and 2.9 percent for 2016 , 2015 and 2014 , respectively. The estimated lives for utility plant for CECONY range from 5 to 85 years for electric and gas, 5 to 80 years for steam and 5 to 55 years for general plant. For O&R, the estimated lives for utility plant range from 5 to 75 years for electric and gas and 5 to 50 years for general plant. Non-Utility Plant Non-utility plant is stated at original cost. For Con Edison, non-utility plant consists primarily of the Clean Energy Businesses’ renewable electric production and gas storage. For the Utilities, non-utility plant consists of land and conduit for telecommunication use. Depreciation on these assets is computed using the straight-line method for financial statement purposes over their estimated useful lives, which range from 3 to 30 years .
Goodwill	Goodwill Con Edison tests goodwill for impairment at least annually or whenever there is a triggering event. There is an option to first make a qualitative assessment of whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount before applying a two-step, quantitative goodwill impairment test. However, Con Edison has not elected to perform the qualitative assessment and exclusively applies the two-step quantitative approach. The first step of the goodwill impairment test compares the estimated fair value of a reporting unit with its carrying value, including goodwill. If the estimated fair value of a reporting unit exceeds its carrying value, goodwill of the reporting unit is considered not impaired. If the carrying value exceeds the estimated fair value of the reporting unit, the second step is performed to measure the amount of impairment loss, if any. The second step requires a calculation of the implied fair value of goodwill.
Long-Lived and Intangible Assets	Long-Lived and Intangible Assets Con Edison evaluates the impairment of long-lived assets and intangible assets with definite lives, based on projections of undiscounted future cash flows, whenever events or changes in circumstances indicate that the carrying amounts of such assets may not be recoverable. In the event an evaluation indicates that such cash flows cannot be expected to be sufficient to fully recover the assets, the assets are written down to their estimated fair value.
Revenues	Revenues The Utilities recognize and, until the sale of its retail electric supply business in September 2016 (see Note U), Con Edison Solutions recognized revenues for energy service on a monthly billing cycle basis. The Utilities defer over a 12 -month period net interruptible gas revenues, other than those authorized by the NYSPSC to be retained by the Utilities, for refund to firm gas sales and transportation customers. The Utilities accrue and Con Edison Solutions accrued revenues at the end of each month for estimated energy service not yet billed to customers. CECONY’s electric and gas rate plans and O&R’s New York electric and gas rate plans each contain a revenue decoupling mechanism under which the company’s actual energy delivery revenues are compared with the authorized delivery revenues and the difference accrued, with interest, for refund to, or recovery from, customers, as applicable. See “Rate Plans” in Note B. The NYSPSC requires utilities to record gross receipts tax revenues and expenses on a gross income statement presentation basis (i.e., included in both revenue and expense). The recovery of these taxes is generally provided for in the revenue requirement within each of the respective NYSPSC approved rate plans.
Recoverable Energy Costs/New York Independent System Operator (NYISO)	Recoverable Energy Costs The Utilities generally recover all of their prudently incurred fuel, purchased power and gas costs, including hedging gains and losses, in accordance with rate provisions approved by the applicable state public utility regulators. If the actual energy supply costs for a given month are more or less than the amounts billed to customers for that month, the difference in most cases is recoverable from or refundable to customers. Differences between actual and billed electric and steam supply costs and costs of its electric demand management programs are generally deferred for charge or refund to customers during the next billing cycle (normally within one or two months ). For the Utilities’ gas costs, differences between actual and billed gas costs during the 12-month period ending each August are charged or refunded to customers during a subsequent 12-month period. New York Independent System Operator (NYISO) The Utilities purchase electricity through the wholesale electricity market administered by the NYISO. The difference between purchased power and related costs initially billed to the Utilities by the NYISO and the actual cost of power subsequently calculated by the NYISO is refunded by the NYISO to the Utilities, or paid to the NYISO by the Utilities. The reconciliation payments or receipts are recoverable from or refundable to the Utilities’ customers. Certain other payments to or receipts from the NYISO are also subject to reconciliation, with shortfalls or amounts in excess of specified rate allowances recoverable from or refundable to customers. These include proceeds from the sale through the NYISO of transmission rights on CECONY’s transmission system (transmission congestion contracts or TCCs).
Temporary Cash Investments	Temporary Cash Investments Temporary cash investments are short-term, highly-liquid investments that generally have maturities of three months or less at the date of purchase. They are stated at cost, which approximates market. The Companies consider temporary cash investments to be cash equivalents.
Investments	Investments Investments consist primarily of the investments of Con Edison Transmission and the Clean Energy Businesses that are accounted for under the equity method and the fair value of the Utilities’ supplemental retirement income plan and deferred income plan assets.
Pension and Other Postretirement Benefits	Pension and Other Postretirement Benefits The accounting rules for retirement benefits require an employer to recognize an asset or liability for the overfunded or underfunded status of its pension and other postretirement benefit plans. For a pension plan, the asset or liability is the difference between the fair value of the plan’s assets and the projected benefit obligation. For any other postretirement benefit plan, the asset or liability is the difference between the fair value of the plan’s assets and the accumulated postretirement benefit obligation. The accounting rules generally require employers to recognize all unrecognized prior service costs and credits and unrecognized actuarial gains and losses in accumulated other comprehensive income/(loss) (OCI), net of tax. Such amounts will be adjusted as they are subsequently recognized as components of total periodic benefit cost or income pursuant to the current recognition and amortization provisions. For the Utilities’ pension and other postretirement benefit plans, regulatory accounting treatment is generally applied in accordance with the accounting rules for regulated operations. Unrecognized prior service costs or credits and unrecognized actuarial gains and losses are recorded to regulatory assets or liabilities, rather than OCI. See Notes E and F. The total periodic benefit costs are recognized in accordance with the accounting rules for retirement benefits. Investment gains and losses are recognized in expense over a 15 -year period and other actuarial gains and losses are recognized in expense over a 10 -year period, subject to the deferral provisions in the rate plans. In accordance with the Statement of Policy issued by the NYSPSC and its current electric, gas and steam rate plans, CECONY defers for payment to or recovery from customers the difference between such expenses and the amounts for such expenses reflected in rates. Generally, O&R also defers such difference pursuant to its rate plans. See Note B. The Companies calculate the expected return on pension and other postretirement benefit plan assets by multiplying the expected rate of return on plan assets by the market-related value (MRV) of plan assets at the beginning of the year, taking into consideration anticipated contributions and benefit payments that are to be made during the year. The accounting rules allow the MRV of plan assets to be either fair value or a calculated value that recognizes changes in fair value in a systematic and rational manner over not more than five years. The Companies use a calculated value when determining the MRV of the plan assets that adjusts for 20 percent of the difference between fair value and expected MRV of plan assets. This calculated value has the effect of stabilizing variability in assets to which the Companies apply the expected return.
Federal Income Tax/State Income Tax	Federal Income Tax In accordance with accounting rules for income taxes, the Companies have recorded an accumulated deferred federal income tax liability at current tax rates for temporary differences between the book and tax basis of assets and liabilities. In accordance with rate plans, the Utilities have recovered amounts from customers for a portion of the tax liability they will pay in the future as a result of the reversal or “turn-around” of these temporary differences. As to the remaining tax liability, the Utilities have established regulatory assets for the net revenue requirements to be recovered from customers for the related future tax expense. See Notes B and L. In 1993, the NYSPSC issued a Policy Statement approving accounting procedures consistent with accounting rules for income taxes and providing assurances that these future increases in taxes will be recoverable in rates. See Note L. Accumulated deferred investment tax credits are amortized ratably over the lives of the related properties and applied as a reduction to future federal income tax expense. Con Edison and its subsidiaries file a consolidated federal income tax return. The consolidated income tax liability is allocated to each member of the consolidated group using the separate return method. Each member pays or receives an amount based on its own taxable income or loss in accordance with a consolidated tax allocation agreement. Tax loss and tax credit carryforwards are allocated among members in accordance with consolidated tax return regulations. State Income Tax Con Edison and its subsidiaries file a combined New York State Corporation Business Franchise Tax Return. Similar to a federal consolidated income tax return, the income of all entities in the combined group is subject to New York State taxation, after adjustments for differences between federal and New York law and apportionment of income among the states in which the company does business. Each member’s share of the New York State tax is based on its own New York State taxable income or loss.
Research and Development Costs	Research and Development Costs Research and development costs are charged to operating expenses as incurred.
Reclassification	Reclassification Certain prior year amounts have been reclassified to conform with the current year presentation.
Earnings Per Common Share	Earnings Per Common Share Con Edison presents basic and diluted earnings per share on the face of its consolidated income statement. Basic earnings per share (EPS) are calculated by dividing earnings available to common shareholders (“Net income” on Con Edison’s consolidated income statement) by the weighted average number of Con Edison common shares outstanding during the period. In the calculation of diluted EPS, weighted average shares outstanding are increased for additional shares that would be outstanding if potentially dilutive securities were converted to common stock. Potentially dilutive securities for Con Edison consist of restricted stock units, deferred stock units and stock options for which the average market price of the common shares for the period was greater than the exercise price.
Estimates	Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
New Financial Accounting Standards	New Financial Accounting Standards In May 2014, the Financial Accounting Standards Board (FASB) and the International Accounting Standards Board jointly issued a revenue recognition standard that will supersede the revenue recognition requirements within Accounting Standards Codification Topic 605, “Revenue Recognition,” and most industry-specific guidance under the Codification through Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” The purpose of the new guidance is to create a consistent framework for revenue recognition. The guidance clarifies how to measure and recognize revenue arising from customer contracts to depict the transfer of goods or services in an amount that reflects the consideration the entity expects to receive. Amendments were issued subsequently to clarify key areas including principal/agent considerations, performance obligations, licensing, sales taxes, noncash consideration, and contracts. The new standard is effective for reporting periods beginning after December 15, 2017. Early adoption is permitted for reporting periods beginning after December 15, 2016, however, the Companies plan to adopt the new standard for reporting periods beginning after December 15, 2017. Under the new standard, companies may use either of the following transition methods: (i) a full retrospective approach reflecting the application of the standard in each prior reporting period with the option to elect certain practical expedients, or (ii) a modified retrospective approach with the cumulative effect of initially adopting ASU 2014-09 recognized at the date of adoption (which includes additional footnote disclosures). The Companies anticipate using the modified retrospective approach. The Companies are currently in the process of evaluating the impact of the new standard on their various revenue streams. The majority of the Companies’ sales are derived from tariffs to provide electric, gas, and steam service to customers. For such tariffs, the Companies expect that the revenue from contracts with the customer under ASU 2014-09 will be equivalent to the electricity, gas, or steam supplied in that period which is consistent with current practice. Consequently, the Companies do not anticipate that the new standard will significantly impact the amount and/or timing of such revenues. The Companies continue to review the potential impacts of other revenue at the Utilities and the Clean Energy Businesses on the Companies' financial position, results of operations and liquidity as well as the additional disclosures required under the new standard. In January 2016, the FASB issued amendments on certain aspects of recognition, measurement, presentation, and disclosure of financial instruments through ASU No. 2016-01, “Financial Instruments (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” The amendments require changes to the accounting for equity investments, the presentation and disclosure requirements for financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, clarification was provided related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. Early adoption is permitted for portions of the standard. The Companies are in the process of evaluating the potential impact of the new guidance on the Companies’ financial position, results of operations and liquidity. In February 2016, the FASB issued amendments on financial reporting of leasing transactions through ASU No. 2016-02, “Leases (Topic 842)." The amendments require lessees to recognize assets and liabilities on the balance sheet and disclose key information about leasing arrangements. Lessees will need to recognize a right-of-use asset and a lease liability for virtually all of their leases (other than leases that meet the definition of a short-term lease). Lessor accounting is similar to the current model, but updated to align with certain changes to the lessee model. For income statement purposes, the pattern of expense recognition will be dependent on whether transactions are designated as operating leases or finance leases. The amendments are effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The amendments must be adopted using a modified retrospective transition and provide for certain practical expedients. Based on the existing portfolio of leases at implementation, for leases currently classified as operating leases, the Companies expect to recognize on the statements of financial position right-of-use assets and lease liabilities. The Companies are in the process of evaluating the potential impact of the new guidance on the Companies’ results of operations and liquidity. In March 2016, the FASB issued amendments to the guidance for Derivatives and Hedging accounting through ASU 2016-05, “Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships." The amendments clarify that a change in the counterparty to a derivative instrument that has been designated as a hedging instrument under Topic 815 does not, in and of itself, require discontinuation of the application of hedge accounting. The amendments in this update are effective for financial statements issued for reporting periods beginning after December 15, 2016. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In March 2016, the FASB issued amendments to clarify the guidance for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts through ASU No. 2016-06, “Derivatives & Hedging (Topic 815): Contingent Put and Call Options in Debt Instruments.” An entity performing the assessment under the amendments is required to assess the embedded call (put) options solely in accordance with the four-step decision sequence. The amendments are effective for financial statements issued for reporting periods beginning after December 15, 2016. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In March 2016, the FASB issued amendments to eliminate the requirement to retroactively adopt the equity method of accounting when a company increases its level of ownership or degree of influence over an investment through ASU No. 2016-07, “Investments-Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting.” The amendments require that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in Accumulated Other Comprehensive Income at the date the investment qualifies for the equity method. The amendments are effective for reporting periods beginning after December 15, 2016. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In March 2016, the FASB issued amendments to simplify several aspects of the accounting for share-based payment transactions through ASU No. 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting.” The amendments simplify areas such as income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The amendments are effective for reporting periods beginning after December 15, 2016. The company elected to early adopt this standard as permitted, and it did not have a material impact on the Companies’ financial position, results of operations and liquidity. In May 2016, the FASB issued amendments to the guidance on revenue recognition and derivatives and hedging through ASU 2016-11, “Revenue Recognition (Topic 605) and Derivatives and Hedging (Topic 815): Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting (SEC Update).” The amendment rescinds certain SEC guidance superseded by the newly issued revenue recognition and hedging guidance (ASU 2014-09 and 2014-16 respectively). The amendments will be effective upon adoption of ASU 2014-09 and 2014-16. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In June 2016, the FASB issued amendments to the guidance for recognition of credit losses for financial instruments through ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” The amendment replaces the incurred loss impairment methodology which involved delayed recognition of credit losses. As the updated guidance now requires credit losses to be recognized when expected rather than when incurred, a broader range of reasonable and supportable information must be considered in developing the credit loss estimates. This includes financial instruments that are valued at amortized cost and available for sale. For public entities, the amendments are effective for reporting periods beginning after December 15, 2019. Early adoption is permitted for reporting periods beginning after December 15, 2018. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In August 2016, the FASB issued amendments to the guidance for the Statement of Cash Flows through ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force).” The amendment specifies the classification and presentation of certain cash flow items to reduce diversity in practice. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In October 2016, the FASB issued amendments to the guidance for Income Taxes through ASU 2016-16, “Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory).” The amendment clarifies the tax treatment of intra-entity transfers of assets other than inventory. The updated guidance requires entities to recognize the income tax consequences of an intra-entity transfer of assets other than inventory when the transfer occurs. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In October 2016, the FASB issued amendments to the guidance for Consolidation through ASU 2016-17, “Consolidation (Topic 810): Interests Held through Related Parties That Are under Common Control.” The amendments in this update change how a single decision maker of a VIE will consider its indirect interests in a VIE held by related parties under common control when performing the primary beneficiary analysis. If a single decision maker and its related parties are under common control, the single decision maker must evaluate indirect interests on a proportionate basis when evaluating whether it is a primary beneficiary of the VIE. The guidance does not change the characteristics of a primary beneficiary under GAAP but has amended the considerations in the evaluation of determining the primary beneficiary of a VIE under common control. For public entities, the amendments are effective for reporting periods beginning after December 15, 2016. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In November 2016, the FASB issued amendments to the guidance for the Statement of Cash Flows through ASU 2016-18, “Update 2016-18-Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force).” The amendments in this update clarify the presentation of changes in restricted cash and restricted cash equivalents in the statement of cash flows. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In January 2017, the FASB issued amendments to the guidance for Business Combinations through ASU 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business.” The amendments in this update clarify the definition of a business and provide guidance on evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. I n January 2017, the FASB issued amendments to the guidance for the subsequent measurement of goodwill through ASU 2017-04, “Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” The amendments in this update simplify goodwill impairment testing by eliminating Step 2 of the goodwill impairment test wherein an entity has to compute the implied fair value of goodwill by performing procedures to determine the fair value of its assets and liabilities. Under the new guidance, an entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value up to the total amount of goodwill allocated to that reporting unit. For public entities, the amendments are effective for reporting periods beginning after December 15, 2019. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity.

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Capitalized Cost of Utility Plant	At December 31, 2016 and 2015 , the capitalized cost of the Companies’ utility plant, net of accumulated depreciation, was as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Electric Generation $479 $459 $479 $459 Transmission 3,184 3,045 2,963 2,833 Distribution 18,150 17,244 17,234 16,394 Gas (a) 6,285 5,698 5,749 5,196 Steam 1,882 1,849 1,882 1,849 General 1,816 1,758 1,639 1,592 Held for future use 74 77 65 65 Construction work in progress 1,175 1,003 1,104 922 Net Utility Plant $33,045 $31,133 $31,115 $29,310 (a) Primarily distribution.
Schedule of Total Excise Taxes Recorded in Operating Revenues	Total excise taxes (inclusive of gross receipts taxes) recorded in operating revenues were as follows: For the Years Ended December 31, (Millions of Dollars) 2016 2015 2014 Con Edison $336 $354 $365 CECONY 316 331 343
Schedule of Equity Method Investments	The following investment assets are included in the Companies' consolidated balance sheets at December 31, 2016 and 2015: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 CET Gas investment in Stagecoach Gas Services, LLC (a) $992 $— $— $— Con Edison Development equity method investments (b) 488 574 — — Supplemental retirement income plan assets (c) 273 243 246 221 Deferred income plan assets 60 55 60 55 CET Electric investment in New York Transco, LLC 51 3 — — CET Gas investment in Mountain Valley Pipeline, LLC 48 — — — Other 9 9 9 10 Total investments $1,921 $884 $315 $286 (a) See Note U. (b) See Note Q. (c) See Note E.
Research and Development Costs	Research and development costs were as follows: For the Years Ended December 31, (Millions of Dollars) 2016 2015 2014 Con Edison $24 $23 $22 CECONY 22 22 20
Basic and Diluted Earnings Per Share	Basic and diluted EPS for Con Edison are calculated as follows: For the Years Ended December 31, (Millions of Dollars, except per share amounts/Shares in Millions) 2016 2015 2014 Net income $1,245 $1,193 $1,092 Weighted average common shares outstanding – basic 300.4 293.0 292.9 Add: Incremental shares attributable to effect of potentially dilutive securities 1.5 1.4 1.1 Adjusted weighted average common shares outstanding – diluted 301.9 294.4 294.0 Net Income per common share – basic $4.15 $4.07 $3.73 Net Income per common share – diluted $4.12 $4.05 $3.71
Changes in Accumulated Other Comprehensive Income/(Loss)	Changes to accumulated other comprehensive income/(loss) (OCI) for Con Edison and CECONY are as follows: (Millions of Dollars) Con Edison CECONY Accumulated OCI, net of taxes, at December 31, 2014 (a) $(45) $(11) OCI before reclassifications, net of tax of $(3) for Con Edison 5 1 Amounts reclassified from accumulated OCI related to pension plan liabilities, net of tax of $(4) and $(1) for Con Edison and CECONY, respectively(a)(b) 6 1 Total OCI, net of taxes, at December 31, 2015 11 2 Accumulated OCI, net of taxes, at December 31, 2015 (a) $(34) $(9) OCI before reclassifications, net of tax of $(1) for Con Edison and CECONY 2 1 Amounts reclassified from accumulated OCI related to pension plan liabilities, net of tax of $(3) and $(1) for Con Edison and CECONY, respectively(a)(b) 5 1 Total OCI, net of taxes, at December 31, 2016 7 2 Accumulated OCI, net of taxes, at December 31, 2016 (a) $(27) $(7) (a) Tax reclassified from accumulated OCI is reported in the income tax expense line item of the consolidated income statement. (b) For the portion of unrecognized pension and other postretirement benefit costs relating to the Utilities, costs are recorded into, and amortized out of, regulatory assets instead of OCI. The net actuarial losses and prior service costs recognized during the period are included in the computation of total periodic pension and other postretirement benefit cost. See Notes E and F.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2016
Public Utilities, General Disclosures [Line Items]
Schedule of Regulatory Assets	Regulatory assets and liabilities at December 31, 2016 and 2015 were comprised of the following items: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Regulatory assets Unrecognized pension and other postretirement costs $2,874 $3,876 $2,730 $3,697 Future income tax 2,439 2,350 2,325 2,232 Environmental remediation costs 823 904 711 800 Revenue taxes 295 253 280 240 Deferred storm costs 56 185 3 110 Deferred derivative losses 48 50 42 46 Unamortized loss on reacquired debt 43 50 41 48 Recoverable energy costs 42 16 38 15 Pension and other postretirement benefits deferrals 38 45 7 16 O&R property tax reconciliation 37 46 — — Surcharge for New York State assessment 28 44 26 40 Preferred stock redemption 25 26 25 26 Net electric deferrals 24 44 24 44 O&R transition bond charges 15 21 — — Workers’ compensation 13 11 13 11 Other 224 175 208 157 Regulatory assets – noncurrent 7,024 8,096 6,473 7,482 Deferred derivative losses 91 113 86 103 Recoverable energy costs 9 19 4 18 Regulatory assets – current 100 132 90 121 Total Regulatory Assets $7,124 $8,228 $6,563 $7,603 Regulatory liabilities Allowance for cost of removal less salvage $755 $676 $641 $570 Pension and other postretirement benefit deferrals 193 76 162 46 Property tax reconciliation 178 303 178 303 Net unbilled revenue deferrals 145 109 145 109 Prudence proceeding 95 99 95 99 Carrying charges on repair allowance and bonus depreciation 68 49 67 48 New York State income tax rate change 61 75 60 72 Unrecognized other postretirement costs 60 28 60 28 Variable-rate tax-exempt debt - cost rate reconciliation 55 70 48 60 Base rate change deferrals 40 128 40 128 Earnings sharing - electric, gas and steam 39 80 28 80 Net utility plant reconciliations 16 32 15 31 Property tax refunds 1 44 1 44 World Trade Center settlement proceeds — 21 — 21 Other 199 187 172 150 Regulatory liabilities – noncurrent 1,905 1,977 1,712 1,789 Revenue decoupling mechanism 71 45 61 45 Refundable energy costs 29 64 5 33 Deferred derivative gains 28 6 24 6 Regulatory liabilities—current 128 115 90 84 Total Regulatory Liabilities $2,033 $2,092 $1,802 $1,873
Schedule of Regulatory Liabilities	Regulatory assets and liabilities at December 31, 2016 and 2015 were comprised of the following items: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Regulatory assets Unrecognized pension and other postretirement costs $2,874 $3,876 $2,730 $3,697 Future income tax 2,439 2,350 2,325 2,232 Environmental remediation costs 823 904 711 800 Revenue taxes 295 253 280 240 Deferred storm costs 56 185 3 110 Deferred derivative losses 48 50 42 46 Unamortized loss on reacquired debt 43 50 41 48 Recoverable energy costs 42 16 38 15 Pension and other postretirement benefits deferrals 38 45 7 16 O&R property tax reconciliation 37 46 — — Surcharge for New York State assessment 28 44 26 40 Preferred stock redemption 25 26 25 26 Net electric deferrals 24 44 24 44 O&R transition bond charges 15 21 — — Workers’ compensation 13 11 13 11 Other 224 175 208 157 Regulatory assets – noncurrent 7,024 8,096 6,473 7,482 Deferred derivative losses 91 113 86 103 Recoverable energy costs 9 19 4 18 Regulatory assets – current 100 132 90 121 Total Regulatory Assets $7,124 $8,228 $6,563 $7,603 Regulatory liabilities Allowance for cost of removal less salvage $755 $676 $641 $570 Pension and other postretirement benefit deferrals 193 76 162 46 Property tax reconciliation 178 303 178 303 Net unbilled revenue deferrals 145 109 145 109 Prudence proceeding 95 99 95 99 Carrying charges on repair allowance and bonus depreciation 68 49 67 48 New York State income tax rate change 61 75 60 72 Unrecognized other postretirement costs 60 28 60 28 Variable-rate tax-exempt debt - cost rate reconciliation 55 70 48 60 Base rate change deferrals 40 128 40 128 Earnings sharing - electric, gas and steam 39 80 28 80 Net utility plant reconciliations 16 32 15 31 Property tax refunds 1 44 1 44 World Trade Center settlement proceeds — 21 — 21 Other 199 187 172 150 Regulatory liabilities – noncurrent 1,905 1,977 1,712 1,789 Revenue decoupling mechanism 71 45 61 45 Refundable energy costs 29 64 5 33 Deferred derivative gains 28 6 24 6 Regulatory liabilities—current 128 115 90 84 Total Regulatory Liabilities $2,033 $2,092 $1,802 $1,873
Rockland Electric Company (RECO)
Public Utilities, General Disclosures [Line Items]
Summary of Utilities Rate Plans	RECO Effective period May 2010 – July 2014 August 2014 – July 2015 (a) Base rate changes Yr. 1 – $9.8 million Yr. 1 – $13.0 million Amortization to income of net regulatory (assets) and liabilities $(3.9) million over four years and $(4.9) million of deferred storm costs over five years $0.4 million over three years and $(25.6) million of deferred storm costs over four years Recoverable energy costs Current rate recovery of purchased power costs. Current rate recovery of purchased power costs. Cost reconciliations None None Average rate base $148.6 million $172.2 million Weighted average cost of capital (after-tax) 8.21 percent 7.83 percent Authorized return on common equity 10.3 percent 9.75 percent Cost of long-term debt 6.16 percent 5.89 percent Common equity ratio 50 percent 50 percent (a) In January 2016, the NJBPU approved RECO’s plan for a 3 -year, $15.7 million electric system storm hardening capital program, the costs of which RECO, beginning in 2017, is collecting through a customer surcharge until a new rate plan is approved that reflects the costs.
Electric | CECONY
Public Utilities, General Disclosures [Line Items]
Summary of Utilities Rate Plans	The following tables contain a summary of the Utilities’ rate plans: CECONY – Electric Effective period January 2014 – December 2016 January 2017 - December 2019 (b) Base rate changes Yr. 1 – $(76.2) million (a) Yr. 1 - $195 million (b) Amortizations to income of net regulatory (assets) and liabilities Yr. 1 and 2 – $(37) million (c) Yr. 1 - $84 million Other revenue sources Retention of $90 million of annual transmission congestion revenues. Retention of $75 million of annual transmission congestion revenues. Revenue decoupling mechanisms In 2014, 2015 and 2016, the company deferred for customer benefit $146 million, $98 million and $101 million of revenues, respectively. Continuation of reconciliation of actual to authorized electric delivery revenues. Recoverable energy costs (d) Current rate recovery of purchased power and fuel costs. Continuation of current rate recovery of purchased power and fuel costs. Negative revenue adjustments Potential penalties (up to $400 million annually) if certain performance targets are not met. In 2014, the company recorded a $5 million negative revenue adjustment. In 2015 and 2016, the company did not record any negative revenue adjustments. Potential penalties if certain performance targets relating to service, reliability, safety and other matters are not met: Cost reconciliations In 2014, 2015 and 2016, the company deferred $57 million, $26 million and $68 million of net regulatory liabilities, respectively (e). Continuation of reconciliation of expenses for pension and other postretirement benefits, variable-rate tax-exempt debt, major storms, property taxes(e), municipal infrastructure support costs(f), the impact of new laws and environmental site investigation and remediation to amounts reflected in rates.(g) Net utility plant reconciliations Target levels reflected in rates were: Target levels reflected in rates: Average rate base Yr. 1 – $17,323 million Yr. 1 - $18,902 million Weighted average cost of capital (after-tax) Yr. 1 – 7.05 percent Yr. 1 - 6.82 percent Authorized return on common equity Yrs. 1 and 2 – 9.2 percent 9.0 percent Earnings sharing Most earnings above an annual earnings threshold of 9.8 percent for Yrs. 1 and 2 and 9.6 percent for Yr. 3 are to be applied to reduce regulatory assets for environmental remediation and other costs. In 2014 the company had no earnings above the threshold. Actual earnings were $44.4 million and $6.5 million above the threshold for 2015 and 2016, respectively. Most earnings above an annual earnings threshold of 9.5 percent are to be applied to reduce regulatory assets for environmental remediation and other costs accumulated in the rate year. Cost of long-term debt Yr. 1 – 5.17 percent Yr. 1 - 4.93 percent Common equity ratio 48 percent 48 percent (a) The impact of these base rate changes was deferred which resulted in a $30 million regulatory liability at December 31, 2015; this amount has been amortized to $0 at December 31, 2016. (b) In January 2017, the NYSPSC approved the September 2016 Joint Proposal for CECONY's electric rate plan for January 2017 through December 2019. The electric base rate increases are in addition to a $48 million increase resulting from the December 2016 expiration of a temporary credit under the prior rate plan. At the NYSPSC’s option, these increases are being implemented with increases of $199 million in each rate year. Base rates reflect recovery by the company of certain costs of its energy efficiency, system peak reduction and electric vehicle programs (Yr. 1 - $20.5 million ; Yr. 2 - $49 million ; and Yr. 3 - $107.5 million ) over a ten -year period, including the overall pre-tax rate of return on such costs. (c) Amounts reflect annual amortization of $107 million of the regulatory asset for deferred Superstorm Sandy and other major storm costs. The costs recoverable from customers were reduced by $4 million . The costs are no longer subject to NYSPSC staff review and the recovery of the costs is no longer subject to refund. In 2016, an additional $123 million of net regulatory liabilities were amortized to income. (d) For transmission service provided pursuant to the open access transmission tariff of PJM Interconnection LLC (PJM), unless and until changed by the NYSPSC, the company will recover all charges incurred associated with the transmission service. Starting in January 2014, PJM submitted to the FERC a series of requests that substantially increase the charges for the transmission service. CECONY has challenged each of these requests. To date, FERC has rejected all but one of CECONY’s protests. In April 2016, CECONY notified PJM that it will not be exercising its option to continue the service beyond April 2017. CECONY is continuing to challenge FERC’s approval of the increased charges that are being incurred through the end of the current contract term. In June 2015 and May 2016, CECONY filed appeals of certain FERC decisions with the U.S. Court of Appeals. (e) Deferrals for property taxes are limited to 90 percent of the difference from amounts reflected in rates, subject to an annual maximum for the remaining difference of not more than a maximum number of basis points (5.0, 7.5 or 10.0 basis points, depending on the year). (f) In general, if actual expenses for municipal infrastructure support (other than company labor) are below the amounts reflected in rates the company will defer the difference for credit to customers, and if the actual expenses are above the amount reflected in rates the company will defer for recovery from customers 80 percent of the difference subject to a maximum deferral of 30 percent of the amount reflected in rates. (g) In addition, amounts reflected in rates relating to the regulatory asset for future income tax and the excess deferred federal income tax liability are subject to reconciliation. The NYSPSC staff is to audit the regulatory asset and the tax liability. Differences resulting from the NYSPSC staff review will be deferred for NYSPSC determination of any amounts to be refunded or collected from customers.
Electric | O&R
Public Utilities, General Disclosures [Line Items]
Summary of Utilities Rate Plans	O&R New York – Electric Effective period July 2012 – June 2015 November 2015 - October 2017 Base rate changes Yr. 1 – $19.4 million Yr. 1 – $9.3 million – $8.8 million Amortizations to income of net regulatory (assets) and liabilities $(32.2) million over three years Yr. 1 – $(8.5) million (a) – $(9.4) million (a) Revenue decoupling mechanisms In 2012, 2013 and 2014, the company deferred for the customer’s benefit $2.6 million, $3.2 million and $(3.4) million, respectively. In 2015 and 2016, the company deferred for the customer’s benefit an immaterial amount and $6.3 million as regulatory liabilities, respectively. Recoverable energy costs Current rate recovery of purchased power and fuel costs. Continuation of current rate recovery of purchased power costs. Negative revenue adjustments Potential penalties (up to $3 million annually) if certain customer service and system reliability performance targets are not met. In 2012, 2013 and 2014, the company did not record any negative revenue adjustments. Potential penalties (up to $4 million annually) if certain performance targets are not met. In 2015 the company recorded $1.25 million in negative revenue adjustments. In 2016, the company did not record any negative revenue adjustments. Cost reconciliations In 2012, 2013 and 2014, the company deferred $7.8 million, $4.1 million and $(0.2) million as a net increase/(decrease) to regulatory assets, respectively. In 2015 and 2016, the company deferred $0.3 million and $7.4 million as net decreases to regulatory assets, respectively. Net utility plant reconciliations Target levels reflected in rates were: Target levels reflected in rates are: – $928 million (b) – $970 million (b) The company increased/(reduced) its regulatory asset by $2.2 million and $(1.9) million in 2015 and 2016, respectively. Average rate base Yr. 1 – $671 million Yr. 1 – $763 million – $805 million Weighted average cost of capital (after-tax) Yr. 1 – 7.61 percent Yr. 1 – 7.10 percent – 7.06 percent Authorized return on common equity Yr. 1 – 9.4 percent 9.0 percent Earnings sharing The company recorded a regulatory liability of $1 million for earnings above the sharing threshold under the rate plan as of December 31, 2014. Most earnings above an annual earnings threshold of 9.6 percent are to be applied to reduce regulatory assets. In 2015, earnings did not exceed the earnings threshold. Actual earnings were $6.1 million above the threshold for 2016. Cost of long-term debt Yr. 1 – 6.07 percent Yr. 1 – 5.42 percent – 5.35 percent Common equity ratio 48 percent 48 percent (a) $59.3 million of the regulatory asset for deferred storm costs is to be recovered from customers over a five year period, including $11.85 million in each of years 1 and 2, $1 million of the regulatory asset for such costs will not be recovered from customers, and all outstanding issues related to Superstorm Sandy and other past major storms prior to November 2014 are resolved. Approximately $4 million of regulatory assets for property tax and interest rate reconciliations will not be recovered from customers. Amounts that will not be recovered from customers were charged-off in June 2015. (b) Excludes electric AMI as to which the company will be required to defer as a regulatory liability the revenue requirement impact of the amount, if any, by which actual average net utility plant balances are less than amounts reflected in rates: $1 million in year 1 and $9 million in year 2.
Gas | CECONY
Public Utilities, General Disclosures [Line Items]
Summary of Utilities Rate Plans	CECONY – Gas Effective period January 2014 – December 2016 January 2017 - December 2019 (b) Base rate changes Yr. 1 – $(54.6) million (a) Yr. 1 - $(5) million (b) Amortizations to income of net regulatory (assets) and liabilities $4 million over three years Yr. 1 - $39 million Other revenue sources Retention of revenues from non-firm customers of up to $65 million and 15 percent of any such revenues above $65 million. The company retained $70 million, $66 million and $65 million of such revenues in 2014, 2015 and 2016, respectively. Retention of annual revenues from non-firm customers of up to $65 million and 15 percent of any such revenues above $65 million. Revenue decoupling mechanisms In 2014, 2015 and 2016, the company deferred $28 million, $54 million and $71 million of regulatory liabilities, respectively. Continuation of reconciliation of actual to authorized gas delivery revenues. Recoverable energy costs Current rate recovery of purchased gas costs. Continuation of current rate recovery of purchased gas costs. Negative revenue adjustments Potential penalties (up to $33 million in 2014, $44 million in 2015, and $56 million in 2016) if certain gas performance targets are not met. In 2014, 2015 and 2016, the company did not record any negative revenue adjustments. Potential penalties if performance targets relating to service, safety and other matters are not met: Cost reconciliations In 2014, 2015 and 2016, the company deferred $38 million, $11 million, and $32 million of net regulatory liabilities, respectively. (c) Continuation of reconciliation of expenses for pension and other postretirement benefits, variable-rate tax-exempt debt, major storms, property taxes, municipal infrastructure support costs, the impact of new laws and environmental site investigation and remediation to amounts reflected in rates.(d) Net utility plant reconciliations Target levels reflected in rates were: Target levels reflected in rates: Average rate base Yr. 1 – $3,521 million Yr. 1 - $4,841 million Weighted average cost of capital Yr. 1 – 7.10 percent Yr. 1 - 6.82 percent Authorized return on common equity 9.3 percent 9.0 percent Earnings sharing Most earnings above an annual earnings threshold of 9.9 percent are to be applied to reduce regulatory assets for environmental remediation and other costs. In 2014, 2015 and 2016, the company had no earnings above the threshold. Most earnings above an annual earnings threshold of 9.5 percent are to be applied to reduce regulatory assets for environmental remediation and other costs accumulated in the rate year. Cost of long-term debt Yr. 1 – 5.17 percent Yr. 1 - 4.93 percent Common equity ratio 48 percent 48 percent (a) The impact of these base rate changes was deferred which resulted in a $32 million regulatory liability at December 31, 2016. (b) In January 2017, the NYSPSC approved the September 2016 Joint Proposal for CECONY's gas rate plan for January 2017 through December 2019. The gas base rate decrease is offset by a $41 million increase resulting from the December 2016 expiration of a temporary credit under the prior rate plan. (c) Deferrals for property taxes are limited to 90 percent of the difference from amounts reflected in rates, subject to an annual maximum for the remaining difference of not more than a 10 basis point impact on return on common equity (d) See footnotes (e), (f) and (g) to the table under "CECONY - Electric" above.
Gas | O&R
Public Utilities, General Disclosures [Line Items]
Summary of Utilities Rate Plans	O&R New York – Gas Effective period November 2009 – December 2014 November 2015 – October 2018 Base rate changes Yr. 1 – $9 million Yr. 1 – $16.4 million – $16.4 million – $5.8 million – $10.6 million collected through a surcharge Amortization to income of net regulatory (assets) and liabilities $(2) million over three years Yr. 1 – $(1.7) million (a) – $(2.1) million (a) – $(2.5) million (a) Revenue decoupling mechanisms In 2012, 2013 and 2014, the company deferred $4.7 million, $0.7 million and $(0.1) million of regulatory liabilities, respectively. In 2015 and 2016, the company deferred $0.8 million regulatory assets and $6.2 million of regulatory liabilities, respectively. Recoverable energy costs Current rate recovery of purchased gas costs. Current rate recovery of purchased gas costs. Negative revenue adjustments Potential penalties (up to $1.4 million annually) if certain operations and customer service requirements are not met. In 2012, 2013 and 2014, the company did not record any negative revenue adjustments. Potential penalties (up to $3.7 million in Yr. 1, $4.7 million in Yr. 2 and $5.8 million in Yr. 3) if certain performance targets are not met. In 2015 and 2016, the company did not record any negative revenue adjustments. Cost reconciliations In 2012, 2013 and 2014, the company deferred $0.7 million, $8.3 million and $8.3 million as net regulatory assets, respectively. In 2015 and 2016, the company deferred $4.5 million and $6.6 million as net regulatory liabilities and assets, respectively. Net utility plant reconciliations The company deferred $0.7 million in 2012 as a regulatory asset and no deferrals were recorded for 2013 or 2014. Target levels reflected in rates are: – $492 million (b) – $518 million (b) – $546 million (b) No deferral was recorded for 2015 and an immaterial amount was recorded as a regulatory liability in 2016. Average rate base Yr. 1 – $280 million Yr. 1 – $366 million – $391 million – $417 million Weighted average cost of capital (after-tax) 8.49 percent Yr. 1 – 7.10 percent – 7.06 percent – 7.06 percent Authorized return on common equity 10.4 percent 9.0 percent Earnings sharing Earnings above an annual earnings threshold of 11.4 percent are to be applied to reduce regulatory assets. In 2012, 2013 and 2014, earnings did not exceed the earnings threshold. Most earnings above an annual earnings threshold of 9.6 percent are to be applied to reduce regulatory assets. In 2015, earnings did not exceed the earnings threshold. Actual earnings were $4 million above the threshold for 2016. Cost of long-term debt 6.81 percent Yr. 1 – 5.42 percent – 5.35 percent – 5.35 percent Common equity ratio 48 percent 48 percent (a) Reflects that the company will not recover from customers a total of approximately $14 million of regulatory assets for property tax and interest rate reconciliations. Amounts that will not be recovered from customers were charged-off in June 2015. (b) Excludes gas AMI as to which the company will be required to defer as a regulatory liability the revenue requirement impact of the amount, if any, by which actual average net utility plant balances are less than amounts reflected in rates: $0.5 million in year 1, $4.2 million in year 2 and $7.2 million in year 3.
Steam | CECONY
Public Utilities, General Disclosures [Line Items]
Summary of Utilities Rate Plans	CECONY – Steam Effective period January 2014 – December 2016 (a) Base rate changes Yr. 1 – $(22.4) million (b) Amortizations to income of net regulatory (assets) and liabilities $37 million over three years Recoverable energy costs Current rate recovery of purchased power and fuel costs. Negative revenue adjustments Potential penalties (up to $1 million annually) if certain steam performance targets are not met. In 2014, 2015 and 2016, the company did not record any negative revenue adjustments. Cost reconciliations (c) In 2014, 2015 and 2016, the company deferred $42 million of net regulatory liabilities, $17 million of net regulatory assets and $8 million of net regulatory liabilities, respectively. Net utility plant reconciliations Target levels reflected in rates were: Average rate base Yr. 1 – $1,511 million Weighted average cost of capital (after-tax) Yr. 1 – 7.10 percent Authorized return on common equity 9.3 percent Earnings sharing Weather normalized earnings above an annual earnings threshold of 9.9 percent are to be applied to reduce regulatory assets for environmental remediation and other costs. In 2014, the company had no earnings above the threshold. Actual earnings were $11.5 million and $7.8 million above the threshold in 2015 and 2016, respectively. Cost of long-term debt Yr. 1 – 5.17 percent Common equity ratio 48 percent (a) Rates determined pursuant to this rate plan continue in effect until a new rate plan is approved by the NYSPSC. (b) The impact of these base rate changes was deferred which resulted in an $8 million regulatory liability at December 31, 2016. (c) Deferrals for property taxes are limited to 90 percent of the difference from amounts reflected in rates, subject to an annual maximum for the remaining difference of not more than a 10 basis point impact on return on common equity.

Capitalization (Tables)

Capitalization (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Long-Term Debt Maturities	Long-term debt maturing in the period 2017 - 2021 is as follows: (Millions of Dollars) Con Edison CECONY 2017 $39 $— 2018 1,688 1,200 2019 574 475 2020 388 350 2021 540 —
Carrying Amounts and Fair Values of Long-Term Debt	The carrying amounts and fair values of long-term debt at December 31, 2016 and 2015 are: (Millions of Dollars) 2016 2015 Long-Term Debt (including current portion) Carrying Amount Fair Value Carrying Amount Fair Value Con Edison $14,774 $16,093 $12,745 $13,856 CECONY $12,073 $13,268 $11,437 $12,427

Pension Benefits (Tables)

Pension Benefits (Tables) - Pension Benefits	12 Months Ended
	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Total Periodic Benefit Costs	The components of the Companies’ total periodic benefit costs for 2016 , 2015 and 2014 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 Service cost – including administrative expenses $275 $297 $227 $258 $279 $211 Interest cost on projected benefit obligation 596 575 572 559 538 536 Expected return on plan assets (947) (886) (832) (898) (840) (789) Recognition of net actuarial loss 596 775 618 565 734 586 Recognition of prior service costs 4 4 4 2 2 2 NET PERIODIC BENEFIT COST $524 $765 $589 $486 $713 $546 Amortization of regulatory asset (a) — 1 2 — 1 2 TOTAL PERIODIC BENEFIT COST $524 $766 $591 $486 $714 $548 Cost capitalized (214) (301) (225) (203) (285) (212) Reconciliation to rate level 54 (74) 118 58 (74) 108 Cost charged to operating expenses $364 $391 $484 $341 $355 $444 (a) Relates to an increase in CECONY’s pension obligation of $45 million from a 1999 special retirement program.
Schedule of Funded Status	The funded status at December 31, 2016 , 2015 and 2014 was as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 CHANGE IN PROJECTED BENEFIT OBLIGATION Projected benefit obligation at beginning of year $14,377 $15,081 $12,197 $13,482 $14,137 $11,429 Service cost – excluding administrative expenses 271 293 221 254 274 206 Interest cost on projected benefit obligation 596 575 572 559 538 536 Net actuarial (gain)/loss (302) (996) 2,641 (282) (931) 2,484 Plan amendments (256) — 6 (259) — — Benefits paid (591) (576) (556) (551) (536) (518) PROJECTED BENEFIT OBLIGATION AT END OF YEAR $14,095 $14,377 $15,081 $13,203 $13,482 $14,137 CHANGE IN PLAN ASSETS Fair value of plan assets at beginning of year $11,759 $11,495 $10,755 $11,141 $10,897 $10,197 Actual return on plan assets 829 126 752 787 118 715 Employer contributions 508 750 578 469 697 535 Benefits paid (591) (576) (556) (551) (536) (518) Administrative expenses (33) (36) (34) (31) (35) (32) FAIR VALUE OF PLAN ASSETS AT END OF YEAR $12,472 $11,759 $11,495 $11,815 $11,141 $10,897 FUNDED STATUS $(1,623) $(2,618) $(3,586) $(1,388) $(2,341) $(3,240) Unrecognized net loss $3,157 $3,909 $4,888 $2,995 $3,704 $4,616 Unrecognized prior service costs (244) 16 20 (258) 3 4 Accumulated benefit obligation 12,655 12,909 13,454 11,806 12,055 12,553
Schedule of Assumptions	The actuarial assumptions were as follows: 2016 2015 2014 Weighted-average assumptions used to determine benefit obligations at December 31: Discount rate 4.25 % 4.25 % 3.90 % Rate of compensation increase CECONY 4.25 % 4.25 % 4.25 % O&R 4.00 % 4.00 % 4.00 % Weighted-average assumptions used to determine net periodic benefit cost for the years ended December 31: Discount rate 4.25 % 3.90 % 4.80 % Expected return on plan assets 7.80 % 7.80 % 8.00 % Rate of compensation increase CECONY 4.25 % 4.25 % 4.35 % O&R 4.00 % 4.00 % 4.25 %
Schedule of Expected Benefit Payments	Based on current assumptions, the Companies expect to make the following benefit payments over the next ten years : (Millions of Dollars) 2017 2018 2019 2020 2021 2022-2026 Con Edison $702 $719 $730 $745 $758 $3,990 CECONY 653 670 679 693 705 3,716
Schedule of Plan Assets Allocations	The asset allocations for the pension plan at the end of 2016 , 2015 and 2014 , and the target allocation for 2017 are as follows: Target Allocation Range Plan Assets at December 31, Asset Category 2017 2016 2015 2014 Equity Securities 52% - 64% 58 % 57 % 58 % Debt Securities 28% - 38% 33 % 33 % 32 % Real Estate 7% - 11% 9 % 10 % 10 % Total 100% 100 % 100 % 100 %
Schedule of Fair Value of Plan Assets	The fair values of the pension plan assets at December 31, 2015 by asset category are as follows: (Millions of Dollars) Level 1 Level 2 Total Investments within the fair value hierarchy U.S. Equity (a) $3,106 $— $3,106 International Equity (b) 2,874 346 3,220 U.S. Government Issued Debt (c) — 2,222 2,222 Corporate Bonds Debt (d) — 1,356 1,356 Structured Assets Debt (e) — 1 1 Other Fixed Income Debt (f) — 170 170 Cash and Cash Equivalents (g) 115 414 529 Futures (h) 161 132 293 Total investments within the fair value hierarchy $6,256 $4,641 $10,897 Investments measured at NAV per share (n) Private Equity (i) 170 Real Estate (j) 1,248 Hedge Funds (k) 233 Total investments valued using NAV per share $1,651 Funds for retiree health benefits (l) (162) (120) (282) Funds for retiree health benefits measured at NAV per share (l)(n) (43) Total funds for retiree health benefits $(325) Investments (excluding funds for retiree health benefits) $6,094 $4,521 $12,223 Pending activities (m) (464) Total fair value of plan net assets $11,759 (a) - (n) Reference is made to footnotes (a) through (n) in the above table of pension plan assets at December 31, 2016 by asset category.
Schedule of Employer Contribution to Defined Savings Plan	The Companies also offer a defined contribution savings plan that covers substantially all employees and made contributions to the plan as follows: For the Years Ended December 31, (Millions of Dollars) 2016 2015 2014 Con Edison $36 $34 $32 CECONY 32 29 27

Other Postretirement Benefits (

Other Postretirement Benefits (Tables) - Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Net Periodic Benefit Costs	The components of the Companies’ total periodic postretirement benefit costs for 2016 , 2015 and 2014 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 Service cost $18 $20 $19 $13 $15 $15 Interest cost on accumulated other postretirement benefit obligation 48 51 60 40 43 52 Expected return on plan assets (77) (78) (77) (67) (68) (68) Recognition of net actuarial loss 5 31 57 3 28 51 Recognition of prior service cost (20) (20) (19) (14) (14) (15) TOTAL PERIODIC POSTRETIREMENT BENEFIT COST $(26) $4 $40 $(25) $4 $35 Cost capitalized 11 (2) (15) 10 (2) (14) Reconciliation to rate level 22 14 10 22 6 2 Cost charged to operating expenses $7 $16 $35 $7 $8 $23
Schedule of Funded Status	The funded status of the programs at December 31, 2016 , 2015 and 2014 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 CHANGE IN BENEFIT OBLIGATION Benefit obligation at beginning of year $1,287 $1,411 $1,395 $1,093 $1,203 $1,198 Service cost 18 20 19 13 15 15 Interest cost on accumulated postretirement benefit obligation 48 51 60 40 43 52 Amendments — — (12) — — — Net actuarial loss/(gain) (57) (103) 47 (52) (85) 28 Benefits paid and administrative expenses (134) (127) (134) (122) (117) (125) Participant contributions 36 35 36 35 34 35 BENEFIT OBLIGATION AT END OF YEAR $1,198 $1,287 $1,411 $1,007 $1,093 $1,203 CHANGE IN PLAN ASSETS Fair value of plan assets at beginning of year $994 $1,084 $1,113 $870 $950 $977 Actual return on plan assets 60 (6) 59 52 (4) 54 Employer contributions 7 6 7 7 6 7 EGWP payments 35 28 12 33 26 11 Participant contributions 36 35 36 35 34 35 Benefits paid (157) (153) (143) (146) (142) (134) FAIR VALUE OF PLAN ASSETS AT END OF YEAR $975 $994 $1,084 $851 $870 $950 FUNDED STATUS $(223) $(293) $(327) $(156) $(223) $(253) Unrecognized net loss/(gain) $(24) $28 $78 $(42) $4 $45 Unrecognized prior service costs (31) (51) (71) (18) (32) (46)
Schedule of Actuarial Assumptions	The actuarial assumptions were as follows: 2016 2015 2014 Weighted-average assumptions used to determine benefit obligations at December 31: Discount Rate CECONY 4.00 % 4.05 % 3.75 % O&R 4.20 % 4.20 % 3.85 % Weighted-average assumptions used to determine net periodic benefit cost for the years ended December 31: Discount Rate CECONY 4.05 % 3.75 % 4.50 % O&R 4.20 % 3.85 % 4.75 % Expected Return on Plan Assets 7.00 % 7.75 % 7.75 %
Schedule of Change of Assumed Health Care Cost Trend Rate	A one-percentage point change in the assumed health care cost trend rate would have the following effects at December 31, 2016 : Con Edison CECONY 1-Percentage-Point (Millions of Dollars) Increase Decrease Increase Decrease Effect on accumulated other postretirement benefit obligation $(4) $26 $(24) $41 Effect on service cost and interest cost components for 2016 1 — (1) 1
Schedule of Expected Benefit Payments	Based on current assumptions, the Companies expect to make the following benefit payments over the next ten years , net of receipt of governmental subsidies: (Millions of Dollars) 2017 2018 2019 2020 2021 2022-2026 Con Edison $86 $85 $83 $80 $78 $375 CECONY 77 75 73 70 68 322
Schedule of Plan Assets Allocations	The asset allocations for CECONY’s other postretirement benefit plans at the end of 2016 , 2015 and 2014 , and the target allocation for 2017 are as follows: Target Allocation Range Plan Assets at December 31, Asset Category 2017 2016 2015 2014 Equity Securities 57%-73% 60 % 59 % 59 % Debt Securities 26%-44% 40 % 41 % 41 % Total 100% 100 % 100 % 100 %
Schedule of Fair Value of Plan Assets	The fair values of the plan assets at December 31, 2016 by asset category as defined by the accounting rules for fair value measurements (see Note P) are as follows: (Millions of Dollars) Level 1 Level 2 Total Equity (a) $— $391 $391 Other Fixed Income Debt (b) — 250 250 Cash and Cash Equivalents (c) — 13 13 Total investments $— $654 $654 Funds for retiree health benefits (d) 165 105 270 Investments (including funds for retiree health benefits) $165 $759 $924 Funds for retiree health benefits measured at net asset value (d)(e) 37 Pending activities (f) 14 Total fair value of plan net assets $975 (a) Equity includes a passively managed commingled index fund benchmarked to the MSCI All Country World Index. (b) Other Fixed Income Debt includes a passively managed commingled index fund benchmarked to the Barclays Capital Aggregate Index. (c) Cash and Cash Equivalents include short term investments and money markets. (d) The Companies set aside funds for retiree health benefits through a separate account within the pension trust, as permitted under Section 401(h) of the Internal Revenue Code of 1986, as amended. In accordance with the Code, the plan’s investments in the 401(h) account may not be used for, or diverted to, any purpose other than providing health benefits for retirees. The net assets held in the 401(h) account are calculated based on a pro-rata percentage allocation of the net assets in the pension plan. The related obligations for health benefits are not included in the pension plan’s obligations and are included in the Companies’ other postretirement benefit obligation. See Note E. (e) In accordance with ASU 2015-07, certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. See Note E. (f) Pending activities include security purchases and sales that have not settled, interest and dividends that have not been received, and reflects adjustments for available estimates at year end. The fair values of the plan assets at December 31, 2015 by asset category (see Note P) are as follows: (Millions of Dollars) Level 1 Level 2 Total Equity (a) $— $393 $393 Other Fixed Income Debt (b) — 260 260 Cash and Cash Equivalents (c) — 7 7 Total investments $— $660 $660 Funds for retiree health benefits (d) 162 120 282 Investments (including funds for retiree health benefits) $162 $780 $942 Funds for retiree health benefits measured at net asset value (d)(e) 43 Pending activities (f) 9 Total fair value of plan net assets $994 (a) - (f) Reference is made to footnotes (a) through (f) in the above table of other postretirement benefit plan assets at December 31, 2016 by asset category.

Environmental Matters (Tables)

Environmental Matters (Tables)	12 Months Ended
	Dec. 31, 2016
Environmental Remediation Obligations [Abstract]
Accrued Liabilities and Regulatory Assets	The accrued liabilities and regulatory assets related to Superfund Sites at December 31, 2016 and 2015 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Accrued Liabilities: Manufactured gas plant sites $664 $679 $567 $579 Other Superfund Sites 89 86 88 86 Total $753 $765 $655 $665 Regulatory assets $823 $904 $711 $800
Environmental Remediation Costs	Environmental remediation costs incurred and insurance recoveries received related to Superfund Sites at December 31, 2016 and 2015 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Remediation costs incurred $34 $37 $21 $34 Insurance recoveries received (a) 1 — 1 — (a) Reduced amount deferred for recovery from customers
Accrued Liability for Asbestos Suits and Workers' Compensation Proceedings	The accrued liability for asbestos suits and workers’ compensation proceedings (including those related to asbestos exposure) and the amounts deferred as regulatory assets for the Companies at December 31, 2016 and 2015 were as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Accrued liability – asbestos suits $8 $8 $7 $7 Regulatory assets – asbestos suits $8 $8 $7 $7 Accrued liability – workers’ compensation $88 $86 $83 $81 Regulatory assets – workers’ compensation $13 $11 $13 $11

Other Material Contingencies (T

Other Material Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Summary of Total Guarantees	A summary, by type and term, of Con Edison’s total guarantees at December 31, 2016 is as follows: Guarantee Type 0 – 3 years 4 – 10 years > 10 years Total (Millions of Dollars) Con Edison Transmission $435 $613 $— $1,048 Energy transactions 603 35 98 736 Renewable electric production projects 439 — 19 458 Other 128 — — 128 Total $1,605 $648 $117 $2,370

Electricity Purchase Agreemen42

Electricity Purchase Agreements (Tables)	12 Months Ended
	Dec. 31, 2016
Regulated Operations [Abstract]
Summary of Significant Terms of Electricity Purchase Agreements	At December 31, 2016 , the significant terms of the electricity purchase agreements with non-utility generators were as follows: Facility Equity Owner Plant Output (MW) Contracted Output (MW) Contract Start Date Contract Term (Years) Brooklyn Navy Yard Brooklyn Navy Yard Cogeneration Partners, LP 322 293 November 1996 40 Linden Cogeneration Cogen Technologies Linden Venture, LP 974 630 May 1992 25 Indian Point Entergy Nuclear Power Marketing, LLC 2,150 500 August 2001 16
Summary of Estimated Capacity and Other Fixed Payments	The future capacity and other fixed payments under the contracts are estimated to be as follows: (Millions of Dollars) 2017 2018 2019 2020 2021 All Years Thereafter Con Edison $178 $125 $120 $76 $54 $710 CECONY 178 125 119 75 54 710
Summary of Capacity, Energy and Other Fixed Payments	The company’s payments under the agreements for capacity, energy and other fixed payments in 2016 , 2015 and 2014 were as follows: For the Years Ended December 31, (Millions of Dollars) 2016 2015 2014 Linden Cogeneration $304 $323 $381 Indian Point 203 226 247 Astoria Energy (a) 50 178 230 Astoria Generating Company 16 — — Brooklyn Navy Yard 119 113 133 Indeck Corinth (b) — 25 80 Selkirk (c) — — 144 Independence (c) — — 97 Total $692 $865 $1,312 (a) Contract term ended in 2016. (b) Contract term ended in 2015. (c) Contract term ended in 2014

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Schedule of Capital Leases	The following assets under capital leases are included in the Companies’ consolidated balance sheets at December 31, 2016 and 2015 : Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 UTILITY PLANT Common $3 $3 $2 $2
Future Minimum Lease Commitments	The future minimum lease commitments for the above assets are as follows: (Millions of Dollars) Con Edison CECONY 2017 $1 $1 2018 1 1 2019 — — 2020 — — 2021 — — All years thereafter — — Total 2 2 Less: amount representing interest — — Present value of net minimum lease payment $2 $2
Future Minimum Rental Payments for Operating Leases	The future minimum lease commitments under the Companies’ operating lease agreements that are not cancellable by the Companies are as follows: (Millions of Dollars) Con Edison CECONY 2017 $61 $53 2018 62 54 2019 61 54 2020 61 54 2021 58 53 All years thereafter 788 696 Total $1,091 $964

Income Tax (Tables)

Income Tax (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax	The components of income tax are as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 State Current $(42) $38 $59 $(1) $48 $66 Deferred 188 93 61 114 82 65 Federal Current (43) (86) (9) 59 77 158 Deferred 604 569 463 435 372 271 Amortization of investment tax credits (9) (9) (6) (4) (5) (5) Total income tax expense $698 $605 $568 $603 $574 $555
Schedule of Differences on Deferred Tax Assets and Liabilities	The tax effects of temporary differences, which gave rise to deferred tax assets and liabilities, are as follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Deferred tax liabilities: Property basis differences $9,446 $8,614 $8,620 $7,922 Regulatory assets: Unrecognized pension and other postretirement costs 1,162 1,562 1,104 1,490 Future income tax 986 947 940 899 Environmental remediation costs 333 365 287 322 Deferred storm costs 23 75 1 45 Other regulatory assets 371 367 321 308 Equity investments 363 295 — — Total deferred tax liabilities $12,684 $12,225 $11,273 $10,986 Deferred tax assets: Accrued pension and other postretirement costs $581 $982 $467 $857 Regulatory liabilities 822 836 728 752 Superfund and other environmental costs 304 308 265 268 Asset retirement obligations 99 97 92 94 Loss carryforwards 59 29 — — Tax credits carryforward 498 258 — 1 Valuation allowance (16) (15) — — Other 303 362 312 292 Total deferred tax assets 2,650 2,857 1,864 2,264 Net deferred tax liabilities $10,034 $9,368 $9,409 $8,722 Unamortized investment tax credits 171 169 41 33 Net deferred tax liabilities and unamortized investment tax credits $10,205 $9,537 $9,450 $8,755
Schedule of Income Tax Reconciliation	Reconciliation of the difference between income tax expense and the amount computed by applying the prevailing statutory income tax rate to income before income taxes is as follows: Con Edison CECONY (% of Pre-tax income) 2016 2015 2014 2016 2015 2014 STATUTORY TAX RATE Federal 35 % 35 % 35 % 35 % 35 % 35 % Changes in computed taxes resulting from: State income tax 4 5 5 4 5 5 Cost of removal (1 ) (5 ) (5 ) (1 ) (5 ) (5 ) Renewable energy credits (1 ) (1 ) — — — — Research and development credits (1 ) — — (1 ) — — Other — — (1 ) (1 ) — (1 ) Effective tax rate 36 % 34 % 34 % 36 % 35 % 34 %
Summary of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amounts of unrecognized tax benefits for Con Edison and CECONY follows: Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 Balance at January 1, $34 $34 $9 $2 $2 $— Additions based on tax positions related to the current year 2 — — 2 — — Additions based on tax positions of prior years 19 1 27 19 — 2 Reductions for tax positions of prior years (13) — (2) (2) — — Reductions from expiration of statute of limitations — (1) — — — — Settlements — — — — — — Balance at December 31, $42 $34 $34 $21 $2 $2

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock-Based Compensation Expense	The following table summarizes stock-based compensation expense recognized by the Companies in the years ended December 31, 2016 , 2015 and 2014 : Con Edison CECONY (Millions of Dollars) 2016 2015 2014 2016 2015 2014 Performance-based restricted stock $42 $27 $22 $36 $23 $19 Time-based restricted stock 2 1 2 2 1 2 Non-employee director deferred stock compensation 2 2 2 2 2 2 Stock purchase plan 4 4 3 4 3 3 Total $50 $34 $29 $44 $29 $26 Income tax benefit $20 $14 $12 $18 $12 $10
Summary of Changes in Status of Stock Options	A summary of changes in the status of stock options as of December 31, 2016 is as follows: Con Edison CECONY Shares Weighted Average Exercise Price Shares Weighted Average Exercise Price Outstanding at December 31, 2015 79,125 $43.50 65,775 $43.50 Exercised 79,125 43.50 65,775 43.50 Forfeited — — — — Outstanding at December 31, 2016 — $— — $—
Summary of Stock Options	The following table summarizes information about stock options for the years ended December 31, 2016 and 2015 : Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Aggregate intrinsic value (a) Options outstanding $— $2 $— $1 Options exercised 2 3 2 3 Cash received by Con Edison for payment of exercise price 3 6 3 5 (a) Aggregate intrinsic value represents the changes in the fair value of all outstanding options from their grant dates to December 31 of the years presented above.
Assumptions Used to Calculate Fair Value of Awards	The assumptions used to calculate the fair value of the awards were as follows: 2016 2015 2014 Risk-free interest rate (a) 0.85% - 1.20% 0.64% - 3.28% 0.23% - 3.07% Expected term (b) 3 years 3 years 3 years Expected share price volatility (c) 17.72% - 18.22% 15.82% 13.14% (a) The risk-free rate is based on the U.S. Treasury zero-coupon yield curve. (b) The expected term of the Performance RSUs equals the vesting period. The Companies do not expect significant forfeitures to occur. (c) Based on historical experience.
Summary of Changes in Status of Performance RSUs	A summary of changes in the status of the Performance RSUs’ TSR and non-TSR portions during the year ended December 31, 2016 is as follows: Con Edison CECONY Weighted Average Grant Date Fair Value (a) Weighted Average Grant Date Fair Value (a) Units TSR Portion (b) Non-TSR Portion (c) Units TSR Portion (b) Non-TSR Portion (c) Non-vested at December 31, 2015 1,078,339 $45.26 $58.08 853,257 $45.37 $58.12 Granted 386,400 83.16 72.10 295,300 82.73 72.34 Vested (351,230) 55.16 57.96 (285,162) 55.21 58.07 Forfeited (26,372) 48.48 61.03 (15,053) 53.61 63.05 Non-vested at December 31, 2016 1,087,137 $55.45 $63.03 848,342 $54.92 $63.00 (a) The TSR and non-TSR Portions each account for 50 percent of the awards’ value. (b) Fair value is determined using the Monte Carlo simulation described above. Weighted average grant date fair value does not reflect any accrual or payment of dividends prior to vesting. (c) Fair value is determined using the market price of one share of Con Edison common stock on the grant date. The market price has not been discounted to reflect that dividends do not accrue and are not payable on Performance RSUs until vesting.
Summary of Changes in Status of Time-Based Awards	A summary of changes in the status of time-based awards during the year ended December 31, 2016 is as follows: Con Edison CECONY Units Weighted Average Grant Date Fair Value Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 64,980 $58.56 61,630 $58.55 Granted 23,000 76.62 21,800 76.62 Vested (20,900) 61.03 (19,800) 61.03 Forfeited (1,100) 60.13 (1,050) 60.43 Non-vested at December 31, 2016 65,980 $64.04 62,580 $64.03

Financial Information by Busi46

Financial Information by Business Segment (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Financial Data for Business Segments	The financial data for the business segments are as follows: As of and for the Year Ended December 31, 2016 (Millions of Dollars) Operating revenues Inter- segment revenues Depreciation and amortization Operating income Other Income (deductions) Interest charges Income taxes on operating income (a) Total assets Capital expenditures CECONY Electric $8,106 $17 $865 $1,847 $2 $459 $495 $30,708 $1,819 Gas 1,508 6 159 357 (1) 105 92 7,553 811 Steam 551 88 82 58 (1) 39 30 2,595 126 Consolidation adjustments — (111) — — — — — — — Total CECONY $10,165 $— $1,106 $2,262 $— $603 $617 $40,856 $2,756 O&R Electric $637 $— $49 $95 $1 $24 $30 $1,949 $114 Gas 184 — 18 35 — 12 10 809 52 Other — — — — — — — — — Total O&R $821 $— $67 $130 $1 $36 $40 $2,758 $166 Clean Energy Businesses $1,091 $7 $42 $183 $21 $34 $53 $2,551 $1,235 Con Edison Transmission — — — (3) 43 6 — 1,150 1,078 Other (b) (2) (7) 1 3 (1) 17 4 940 — Total Con Edison $12,075 $— $1,216 $2,575 $64 $696 $714 $48,255 $5,235 As of and for the Year Ended December 31, 2015 (Millions of Dollars) Operating revenues Inter- segment revenues Depreciation and amortization Operating income Other Income (deductions) Interest charges Income taxes on operating income (a) Total assets (c) Capital expenditures CECONY Electric $8,172 $18 $820 $1,798 $(2) $447 $447 $30,603 $1,658 Gas 1,527 6 142 356 (2) 96 100 6,974 671 Steam 629 86 78 93 (1) 41 41 2,653 106 Consolidation adjustments — (110) — — — — — — — Total CECONY $10,328 $— $1,040 $2,247 $(5) $584 $588 $40,230 $2,435 O&R Electric $663 $— $50 $103 $(2) $23 $31 $2,140 $114 Gas 182 — 18 18 (2) 12 2 579 46 Other — — — — — — — — — Total O&R $845 $— $68 $121 $(4) $35 $33 $2,719 $160 Clean Energy Businesses $1,383 $(2) $22 $58 $35 $11 $22 $1,680 $823 Con Edison Transmission — — — — — — — 3 — Other (b) (2) 2 — 1 (2) 23 1 1,010 — Total Con Edison $12,554 $— $1,130 $2,427 $24 $653 $644 $45,642 $3,418 As of and for the Year Ended December 31, 2014 (Millions of Dollars) Operating revenues Inter- segment revenues Depreciation and amortization Operating income Other Income (deductions) Interest charges Income taxes on operating income (a) Total assets (c) Capital expenditures CECONY Electric $8,437 $16 $781 $1,712 $8 $412 $425 $30,295 $1,500 Gas 1,721 6 132 314 2 89 88 6,478 549 Steam 628 84 78 113 1 36 49 2,670 83 Consolidation adjustments — (106) — — — — — — — Total CECONY $10,786 $— $991 $2,139 $11 $537 $562 $39,443 $2,132 O&R Electric $680 $— $46 $103 $3 $24 $29 $2,023 $105 Gas 212 — 15 25 — 10 6 786 37 Other — — — — — 1 — 1 — Total O&R $892 $— $61 $128 $3 $35 $35 $2,810 $142 Clean Energy Businesses $1,244 $(10) $19 $(60) $28 $(8) $(8) $1,013 $447 Con Edison Transmission — — — — — — — 1 — Other (b) (3) 10 — 2 — 27 — 804 — Total Con Edison $12,919 $— $1,071 $2,209 $42 $591 $589 $44,071 $2,721 (a) For Con Edison, the income tax expense on non-operating income was $16 million , $40 million and $21 million in 2016 , 2015 and 2014 , respectively. For CECONY, the income tax expense on non-operating income was $14 million , $14 million and $7 million in 2016 , 2015 and 2014 , respectively. (b) Parent company and consolidation adjustments. Other does not represent a business segment. (c) Reflects $237 million in 2014, related to the adoption of ASU No. 2015-03, “Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs” and ASU No. 2015-17, “Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes.” See Notes C and L.

Derivative Instruments and He47

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Offsetting of Liabilities	The fair values of the Companies’ commodity derivatives including the offsetting of assets and liabilities on the consolidated balance sheet at December 31, 2016 and 2015 were: (Millions of Dollars) 2016 2015 Balance Sheet Location Gross Amounts of Recognized Assets/ (Liabilities) Gross Amounts Offset Net Amounts of Assets/(Liabilities) (a) Gross Amounts of Recognized Assets/ (Liabilities) Gross Amounts Offset Net Amounts of Assets/(Liabilities) (a) Con Edison Fair value of derivative assets Current $81 $(64) $17 (b) $59 $(41) $18 (b) Current - assets held for sale (c) — — — 51 (50) 1 Noncurrent 49 (43) 6 57 (54) 3 Noncurrent - assets held for sale (c) — — — 15 (15) — Total fair value of derivative assets $130 $(107) $23 $182 $(160) $22 Fair value of derivative liabilities Current $(138) $61 $(77) $(144) $78 $(66) Current - liabilities held for sale (c) — — — (115) 50 (65) Noncurrent (91) 52 (39) (d) (102) 63 (39) Noncurrent - liabilities held for sale (c) — — — (28) 15 (13) Total fair value of derivative liabilities $(229) $113 $(116) $(389) $206 $(183) Net fair value derivative assets/(liabilities) $(99) $6 $(93) (b)(d) $(207) $46 $(161) (b) CECONY Fair value of derivative assets Current $52 $(45) $7 (b) $40 $(32) $8 (b) Noncurrent 41 (35) 6 48 (47) 1 Total fair value of derivative assets $93 $(80) $13 $88 $(79) $9 Fair value of derivative liabilities Current $(111) $45 $(66) $(121) $71 $(50) Noncurrent (77) 44 (33) (92) 56 (36) Total fair value of derivative liabilities $(188) $89 $(99) $(213) $127 $(86) Net fair value derivative assets/(liabilities) $(95) $9 $(86) (b) $(125) $48 $(77) (b) (a) Derivative instruments and collateral were offset on the consolidated balance sheet as applicable under the accounting rules. The Companies enter into master agreements for their commodity derivatives. These agreements typically provide offset in the event of contract termination. In such case, generally the non-defaulting party’s payable will be offset by the defaulting party’s payable. The non-defaulting party will customarily notify the defaulting party within a specific time period and come to an agreement on the early termination amount. (b) At December 31, 2016 and 2015 , margin deposits for Con Edison ( $7 million and $26 million , respectively) and CECONY ( $7 million and $26 million , respectively) were classified as derivative assets on the consolidated balance sheet, but not included in the table. Margin is collateral, typically cash, that the holder of a derivative instrument is required to deposit in order to transact on an exchange and to cover its potential losses with its broker or the exchange. (c) Amounts represent derivative assets and liabilities included in assets and liabilities held for sale on the consolidated balance sheet. (d) Does not include ($1) million for interest rate swap (see below).
Offsetting of Assets	The fair values of the Companies’ commodity derivatives including the offsetting of assets and liabilities on the consolidated balance sheet at December 31, 2016 and 2015 were: (Millions of Dollars) 2016 2015 Balance Sheet Location Gross Amounts of Recognized Assets/ (Liabilities) Gross Amounts Offset Net Amounts of Assets/(Liabilities) (a) Gross Amounts of Recognized Assets/ (Liabilities) Gross Amounts Offset Net Amounts of Assets/(Liabilities) (a) Con Edison Fair value of derivative assets Current $81 $(64) $17 (b) $59 $(41) $18 (b) Current - assets held for sale (c) — — — 51 (50) 1 Noncurrent 49 (43) 6 57 (54) 3 Noncurrent - assets held for sale (c) — — — 15 (15) — Total fair value of derivative assets $130 $(107) $23 $182 $(160) $22 Fair value of derivative liabilities Current $(138) $61 $(77) $(144) $78 $(66) Current - liabilities held for sale (c) — — — (115) 50 (65) Noncurrent (91) 52 (39) (d) (102) 63 (39) Noncurrent - liabilities held for sale (c) — — — (28) 15 (13) Total fair value of derivative liabilities $(229) $113 $(116) $(389) $206 $(183) Net fair value derivative assets/(liabilities) $(99) $6 $(93) (b)(d) $(207) $46 $(161) (b) CECONY Fair value of derivative assets Current $52 $(45) $7 (b) $40 $(32) $8 (b) Noncurrent 41 (35) 6 48 (47) 1 Total fair value of derivative assets $93 $(80) $13 $88 $(79) $9 Fair value of derivative liabilities Current $(111) $45 $(66) $(121) $71 $(50) Noncurrent (77) 44 (33) (92) 56 (36) Total fair value of derivative liabilities $(188) $89 $(99) $(213) $127 $(86) Net fair value derivative assets/(liabilities) $(95) $9 $(86) (b) $(125) $48 $(77) (b) (a) Derivative instruments and collateral were offset on the consolidated balance sheet as applicable under the accounting rules. The Companies enter into master agreements for their commodity derivatives. These agreements typically provide offset in the event of contract termination. In such case, generally the non-defaulting party’s payable will be offset by the defaulting party’s payable. The non-defaulting party will customarily notify the defaulting party within a specific time period and come to an agreement on the early termination amount. (b) At December 31, 2016 and 2015 , margin deposits for Con Edison ( $7 million and $26 million , respectively) and CECONY ( $7 million and $26 million , respectively) were classified as derivative assets on the consolidated balance sheet, but not included in the table. Margin is collateral, typically cash, that the holder of a derivative instrument is required to deposit in order to transact on an exchange and to cover its potential losses with its broker or the exchange. (c) Amounts represent derivative assets and liabilities included in assets and liabilities held for sale on the consolidated balance sheet. (d) Does not include ($1) million for interest rate swap (see below).
Realized and Unrealized Gains or Losses on Commodity Derivatives	The following table presents the realized and unrealized gains or losses on commodity derivatives that have been deferred or recognized in earnings for the years ended December 31, 2016 and 2015 : Con Edison CECONY (Millions of Dollars) Balance Sheet Location 2016 2015 2016 2015 Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: Current Deferred derivative gains $23 $1 $18 $2 Noncurrent Deferred derivative gains 1 1 2 — Total deferred gains/(losses) $24 $2 $20 $2 Current Deferred derivative losses $22 $(16) $18 $(11) Current Recoverable energy costs (212) (136) (194) (127) Noncurrent Deferred derivative losses 2 (25) 4 (23) Total deferred gains/(losses) $(188) $(177) $(172) $(161) Net deferred gains/(losses) $(164) $(175) $(152) $(159) Income Statement Location Pre-tax gain/(loss) recognized in income Purchased power expense $(101) (a) $(109) (b) $— $— Gas purchased for resale (112) (106) — — Non-utility revenue 9 (a) 30 (b) — — Other operations and maintenance expense 1 (c) (1) (d) 1 (c) (1) (d) Total pre-tax gain/(loss) recognized in income $(203) $(186) $1 $(1) (a) For the year ended December 31, 2016 , Con Edison recorded unrealized pre-tax gains and losses in non-utility operating revenue ( $5 million loss) and purchased power expense ( $11 million gain). (b) For the year ended December 31, 2015 , Con Edison recorded unrealized pre-tax gains and losses in non-utility operating revenue ( $1 million gain) and purchased power expense ( $1 million loss). (c) For the year ended December 31, 2016 , Con Edison and CECONY recorded an unrealized gain in other operations and maintenance expense ( $1 million ). (d) For the year ended December 31, 2015 , Con Edison and CECONY recorded an unrealized loss in other operations and maintenance expense ( $1 million ).
Hedged Volume of Derivative Transactions	The following table presents the hedged volume of Con Edison’s and CECONY’s derivative transactions at December 31, 2016 : Electric Energy (MWh) (a)(b) Capacity (MW) (a) Natural Gas (Dt) (a)(b) Refined Fuels (gallons) Con Edison 21,235,830 13,616 77,248,786 3,696,000 CECONY 19,258,400 7,500 71,060,000 3,696,000 (a) Volumes are reported net of long and short positions, except natural gas collars where the volumes of long positions are reported. (b) Excludes electric congestion and gas basis swap contracts which are associated with electric and gas contracts and hedged volumes.
Aggregate Fair Value of Companies' Derivative Instruments with Credit-Risk-Related Contingent Features	The following table presents the aggregate fair value of the Companies’ derivative instruments with credit-risk-related contingent features that are in a net liability position, the collateral posted for such positions and the additional collateral that would have been required to be posted had the lowest applicable credit rating been reduced one level and to below investment grade at December 31, 2016 : (Millions of Dollars) Con Edison (a) CECONY (a) Aggregate fair value – net liabilities $113 $103 Collateral posted 43 42 Additional collateral (b) (downgrade one level from current ratings) 11 10 Additional collateral (b)(c) (downgrade to below investment grade from current ratings) 75 65 (a) Non-derivative transactions for the purchase and sale of electricity and gas and qualifying derivative instruments, which have been designated as normal purchases or normal sales, are excluded from the table. These transactions primarily include purchases of electricity from independent system operators. In the event the Utilities and the Clean Energy Businesses were no longer extended unsecured credit for such purchases, the Companies would be required to post additional collateral of $43 million at December 31, 2016 . For certain other such non-derivative transactions, the Companies could be required to post collateral under certain circumstances, including in the event counterparties had reasonable grounds for insecurity. (b) The Companies measure the collateral requirements by taking into consideration the fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liabilities position plus amounts owed to counterparties for settled transactions and amounts required by counterparties for minimum financial security. The fair value amounts represent unrealized losses, net of any unrealized gains where the Companies have a legally enforceable right to offset. (c) Derivative instruments that are net assets have been excluded from the table. At December 31, 2016 , if Con Edison had been downgraded to below investment grade, it would have been required to post additional collateral for such derivative instruments of $15 million .

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis for the years ended December 31, 2016 and 2015 are summarized below. 2016 2015 (Millions of Dollars) Level 1 Level 2 Level 3 Netting Adjustment (e) Total Level 1 Level 2 Level 3 Netting Adjustment (e) Total Con Edison Derivative assets: Commodity (a)(b)(c) $14 $33 $7 $(24) $30 $2 $25 $13 $7 $47 Commodity held for sale (f) — — — — — — 63 1 (63) 1 Other (a)(b)(d) 222 111 — — 333 185 112 — — 297 Total assets $236 $144 $7 $(24) $363 $187 $200 $14 $(56) $345 Derivative liabilities: Commodity (a)(b)(c) $4 $144 $6 $(38) $116 $16 $153 $1 $(65) $105 Interest Rate Swap (a)(b)(c)(g) — 1 — — 1 — — — — — Commodity held for sale (f) — — — — — 1 133 7 (63) 78 Total liabilities $4 $145 $6 $(38) $117 $17 $286 $8 $(128) $183 CECONY Derivative assets: Commodity (a)(b)(c) $10 $19 $1 $(10) $20 $1 $9 $8 $17 $35 Other (a)(b)(d) 200 106 — — 306 171 105 — — 276 Total assets $210 $125 $1 $(10) $326 $172 $114 $8 $17 $311 Derivative liabilities: Commodity (a)(b)(c) $1 $124 $— $(26) $99 $14 $129 $— $(57) $86 (a) The Companies’ policy is to review the fair value hierarchy and recognize transfers into and transfers out of the levels at the end of each reporting period. There were no transfers between levels 1 , 2 and 3 for the years ended December 31, 2016 and 2015 . (b) Level 2 assets and liabilities include investments held in the deferred compensation plan and/or non-qualified retirement plans, interest rate swap, exchange-traded contracts where there is insufficient market liquidity to warrant inclusion in Level 1, certain over-the-counter derivative instruments for electricity, refined products and natural gas. Derivative instruments classified as Level 2 are valued using industry standard models that incorporate corroborated observable inputs; such as pricing services or prices from similar instruments that trade in liquid markets, time value and volatility factors. (c) The accounting rules for fair value measurements and disclosures require consideration of the impact of nonperformance risk (including credit risk) from a market participant perspective in the measurement of the fair value of assets and liabilities. At December 31, 2016 and 2015 , the Companies determined that nonperformance risk would have no material impact on their financial position or results of operations. (d) Other assets are comprised of assets such as life insurance contracts within the deferred compensation plan and non-qualified retirement plans. (e) Amounts represent the impact of legally-enforceable master netting agreements that allow the Companies to net gain and loss positions and cash collateral held or placed with the same counterparties. (f) Amounts represent derivative assets and liabilities included in Assets and Liabilities held for sale on the consolidated balance sheet (see Note U). (g) See Note O.
Schedule of Commodity Derivatives	The risk management group reports to the Companies’ Vice President and Treasurer. Fair Value of Level 3 at December 31, 2016 (Millions of Dollars) Valuation Techniques Unobservable Inputs Range Con Edison — Commodity Electricity $(1) Discounted Cash Flow Forward energy prices (a) $37.75-$55.00 per MWh Discounted Cash Flow Forward capacity prices (a) $2.42-$10.25 per kW-month Transmission Congestion Contracts/Financial Transmission Rights 2 Discounted Cash Flow Discount to adjust auction prices for inter-zonal forward price curves (b) 50.0% Discount/(premium) to adjust auction prices for historical monthly realized settlements (b) (75.2)%-58.9% Inter-zonal forward price curves adjusted for historical zonal losses (b) $1.11-$2.90 per MWh Total Con Edison — Commodity $1 CECONY — Commodity Transmission Congestion Contracts $1 Discounted Cash Flow Discount to adjust auction prices for inter-zonal forward price curves (b) 50.0% Discount/(premium) to adjust auction prices for historical monthly realized settlements (b) (75.2)%-58.9% (a) Generally, increases/(decreases) in this input in isolation would result in a higher/(lower) fair value measurement. (b) Generally, increases/(decreases) in this input in isolation would result in a lower/(higher) fair value measurement.
Reconciliation of Beginning and Ending Net Balances for Assets and Liabilities Measured at Level 3 Fair Value	The table listed below provides a reconciliation of the beginning and ending net balances for assets and liabilities measured at fair value for the years ended December 31, 2016 and 2015 and classified as Level 3 in the fair value hierarchy: Con Edison CECONY (Millions of Dollars) 2016 2015 2016 2015 Beginning balance as of January 1, $6 $20 $8 $13 Included in earnings (7) (20) (1) (6) Included in regulatory assets and liabilities (6) 1 (6) — Purchases 4 11 2 5 Sales (a) 4 — — — Settlements — (6) (2) (4) Ending balance as of December 31, $1 $6 $1 $8 (a) Amounts represent derivative instruments novated as part of the assets of Con Edison Solutions’ retail electric supply business which were sold to a subsidiary of Exelon Corporation (see Note U).

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Business Acquisitions, by Acquisition	(Millions of Dollars) 2016 2015 Restricted cash $8 $9 Receivable from parent company 35 32 Non-utility property, less accumulated depreciation of $9 and $5, respectively 104 107 Other assets 8 11 Total assets (a) $155 $159 Long-term debt due within one year $3 $2 Other liabilities 38 37 Long-term debt 60 62 Total liabilities (b) $101 $101 (a) The assets of Texas Solar 4 represent assets of a consolidated VIE that can be used only to settle obligations of the consolidated VIE. (b) The liabilities of Texas Solar 4 represent liabilities of a consolidated VIE for which creditors do not have recourse to the general credit of the primary beneficiary.
Summary of VIEs	The following table summarizes the VIEs in which Con Edison Development has entered into as of December 31, 2016 : Project Name (a) Generating Capacity (b) (MW AC) Power Purchase Agreement Term in Years Year of Initial Investment Location Maximum Millions of Dollars ) (c) Copper Mountain Solar 3 128 20 2014 Nevada $179 Mesquite Solar 1 83 20 2013 Arizona 108 Copper Mountain Solar 2 75 25 2013 Nevada 84 California Solar 55 25 2012 California 69 Broken Bow II 38 25 2014 Nebraska 48 Texas Solar 4 32 25 2014 Texas 47 (a) With the exception of Texas Solar 4, Con Edison’s ownership interest is 50 percent and these projects are accounted for using the equity method of accounting. With the exception of Texas Solar 4, Con Edison is not the primary beneficiary since the power to direct the activities that most significantly impact the economics of the entities are shared equally between Con Edison Development and third parties. Con Edison’s ownership interest in Texas Solar 4 is 80 percent and is consolidated in the financial statements. Con Edison is the primary beneficiary since the power to direct the activities that most significantly impact the economics of Texas Solar 4 is held by Con Edison Development. (b) Represents Con Edison Development’s ownership interest in the project. (c) For investments accounted for under the equity method, maximum exposure is equal to the carrying value of the investment on the consolidated balance sheet. For consolidated investments, such as Texas Solar 4, maximum exposure is equal to the net assets of the project on the consolidated balance sheet less any applicable noncontrolling interest ( $7 million for Texas Solar 4). Con Edison did not provide any financial or other support during the year that was not previously contractually required.

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Summary of Costs of Administrative and Other Services Provided and Received	The costs of administrative and other services provided by CECONY to, and received by it from, Con Edison and its other subsidiaries for the years ended December 31, 2016 , 2015 and 2014 were as follows: CECONY (Millions of Dollars) 2016 2015 2014 Cost of services provided $108 $99 $90 Cost of services received 64 60 57

General (Details)

General (Details)	12 Months Ended
	Dec. 31, 2016subsidiaryregistrant
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of registrants | registrant	2
Number of regulated subsidiaries | subsidiary	2

Summary of Significant Accoun52

Summary of Significant Accounting Policies - Plant and Depreciation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Public Utility, Property, Plant and Equipment [Line Items]
Annual aggregate depreciation allowance	$ 1,176
Non Utility Plant | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	3 years
Non Utility Plant | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	30 years
CECONY
Public Utility, Property, Plant and Equipment [Line Items]
Annual aggregate depreciation allowance	$ 1,106
AFUDC rates (percent)	4.70%	4.40%	1.60%
Average depreciation rates (percent)	3.10%	3.10%	3.10%
CECONY | Electric | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
CECONY | Electric | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	85 years
CECONY | Gas | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
CECONY | Gas | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	85 years
CECONY | Steam | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
CECONY | Steam | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	80 years
CECONY | General Plant | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
CECONY | General Plant | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	55 years
O&R
Public Utility, Property, Plant and Equipment [Line Items]
AFUDC rates (percent)	3.50%	0.40%	2.60%
Average depreciation rates (percent)	2.90%	3.00%	2.90%
O&R | Electric | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
O&R | Electric | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	75 years
O&R | Gas | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
O&R | Gas | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	75 years
O&R | General Plant | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
O&R | General Plant | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	50 years

Summary of Significant Accoun53

Summary of Significant Accounting Policies - Capitalized Cost of Utility Plant (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Public Utility, Property, Plant and Equipment [Line Items]
General	$ 2,719	$ 2,622
Held for future use	74	77
Construction work in progress	1,175	1,003
NET UTILITY PLANT	33,045	31,133
Electric Generation
Public Utility, Property, Plant and Equipment [Line Items]
Generation	479	459
Electric Transmission
Public Utility, Property, Plant and Equipment [Line Items]
Transmission	3,184	3,045
Electric Distribution
Public Utility, Property, Plant and Equipment [Line Items]
Distribution	18,150	17,244
Gas
Public Utility, Property, Plant and Equipment [Line Items]
Gas	6,285	5,698
Steam
Public Utility, Property, Plant and Equipment [Line Items]
Steam	1,882	1,849
General
Public Utility, Property, Plant and Equipment [Line Items]
General	1,816	1,758
CECONY
Public Utility, Property, Plant and Equipment [Line Items]
General	2,490	2,411
Held for future use	65	65
Construction work in progress	1,104	922
NET UTILITY PLANT	31,115	29,310
CECONY | Electric Generation
Public Utility, Property, Plant and Equipment [Line Items]
Generation	479	459
CECONY | Electric Transmission
Public Utility, Property, Plant and Equipment [Line Items]
Transmission	2,963	2,833
CECONY | Electric Distribution
Public Utility, Property, Plant and Equipment [Line Items]
Distribution	17,234	16,394
CECONY | Gas
Public Utility, Property, Plant and Equipment [Line Items]
Gas	5,749	5,196
CECONY | Steam
Public Utility, Property, Plant and Equipment [Line Items]
Steam	1,882	1,849
CECONY | General
Public Utility, Property, Plant and Equipment [Line Items]
General	$ 1,639	$ 1,592

Summary of Significant Accoun54

Summary of Significant Accounting Policies - Goodwill (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Accounting Policies [Abstract]
Goodwill, impairment charge	$ 15

Summary of Significant Accoun55

Summary of Significant Accounting Policies - Long-Lived and Intangible Assets (Details) - USD ($)	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges		$ 0		$ 0
Discontinued Operations, Held-for-sale | Pike
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charge on assets held for sale	$ 5,000,000		$ 5,000,000

Summary of Significant Accoun56

Summary of Significant Accounting Policies - Revenues (Details)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Revenue deferral period (months)	12 months

Summary of Significant Accoun57

Summary of Significant Accounting Policies - Schedule of Total Excise Taxes Recorded in Operating Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Excise Taxes [Line Items]
Excise taxes	$ 336	$ 354	$ 365
CECONY
Schedule of Excise Taxes [Line Items]
Excise taxes	$ 316	$ 331	$ 343

Summary of Significant Accoun58

Summary of Significant Accounting Policies - Recoverable Energy Costs (Details)	12 Months Ended
	Dec. 31, 2016
Minimum
Public Utilities, General Disclosures [Line Items]
Recovery or refund of energy costs, deferral period	1 month
Maximum
Public Utilities, General Disclosures [Line Items]
Recovery or refund of energy costs, deferral period	2 months

Summary of Significant Accoun59

Summary of Significant Accounting Policies - Investments (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 488	$ 574
Supplemental retirement income plan assets	273	243
Deferred income plan assets	60	55
Other	9	9
Total investments	1,921	884
Stagecoach Gas Services, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	992
Mountain Valley Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	48
CET | Stagecoach Gas Services, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	992	0
CET | New York Transco, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	51	3
CET | Mountain Valley Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	48	0
CECONY
Schedule of Equity Method Investments [Line Items]
Equity method investments	0	0
Supplemental retirement income plan assets	246	221
Deferred income plan assets	60	55
Other	9	10
Total investments	315	286
CECONY | CET | Stagecoach Gas Services, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	0	0
CECONY | CET | New York Transco, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	0	0
CECONY | CET | Mountain Valley Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 0	$ 0

Summary of Significant Accoun60

Summary of Significant Accounting Policies - Pension and Other Postretirement Benefits (Details)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Investment gains and losses recognized, time period (years)	15 years
Other actuarial gains and losses recognized, time period (years)	10 years
Difference between fair value and expected market related value of plan assets (percent)	20.00%

Summary of Significant Accoun61

Summary of Significant Accounting Policies - Research and Development Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Research and Development Expenses [Line Items]
Research and development costs	$ 24	$ 23	$ 22
CECONY
Research and Development Expenses [Line Items]
Research and development costs	$ 22	$ 22	$ 20

Summary of Significant Accoun62

Summary of Significant Accounting Policies - Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Net income	$ 1,245	$ 1,193	$ 1,092
Weighted average common shares outstanding – basic	300.4	293	292.9
Add: Incremental shares attributable to effect of potentially dilutive securities	1.5	1.4	1.1
Adjusted weighted average common shares outstanding – diluted	301.9	294.4	294
Net income per common share — basic (dollars per share)	$ 4.15	$ 4.07	$ 3.73
Net income per common share — diluted (dollars per share)	$ 4.12	$ 4.05	$ 3.71

Summary of Significant Accoun63

Summary of Significant Accounting Policies - Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
AOCI Attributable to Parent, Net of Tax [Roll Forward]
BALANCE AS OF BEGINNING OF PERIOD	$ 13,061	$ 12,585	$ 12,245
TOTAL OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES	7	11	(20)
BALANCE AS OF END OF PERIOD	14,306	13,061	12,585
OCI before reclassifications, tax	(1)	(3)
Accumulated OCI
AOCI Attributable to Parent, Net of Tax [Roll Forward]
BALANCE AS OF BEGINNING OF PERIOD	(34)	(45)	(25)
TOTAL OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES	7	11	(20)
BALANCE AS OF END OF PERIOD	(27)	(34)	(45)
Pension Plan Liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
OCI before reclassifications, net of tax	2	5
Amounts reclassified from accumulated OCI related to pension plan liabilities, net of tax	5	6
TOTAL OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES	7	11
Amounts reclassified from accumulated OCI related to pension plan liabilities, tax	(3)	(4)
CECONY
AOCI Attributable to Parent, Net of Tax [Roll Forward]
TOTAL OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES	2	2	(5)
OCI before reclassifications, tax	(1)
CECONY | Accumulated OCI
AOCI Attributable to Parent, Net of Tax [Roll Forward]
BALANCE AS OF BEGINNING OF PERIOD	(9)	(11)
TOTAL OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES	2	2	(5)
BALANCE AS OF END OF PERIOD	(7)	(9)	$ (11)
CECONY | Pension Plan Liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
OCI before reclassifications, net of tax	1	1
Amounts reclassified from accumulated OCI related to pension plan liabilities, net of tax	1	1
TOTAL OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES	2	2
Amounts reclassified from accumulated OCI related to pension plan liabilities, tax	$ (1)	$ (1)

Regulatory Matters - Summary of

Regulatory Matters - Summary of Utilities Rate Plans (CECONY-Electric) (Details) - USD ($)	1 Months Ended	12 Months Ended			36 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2019	Dec. 31, 2016
Public Utilities, General Disclosures [Line Items]
Cost reconciliations, deferred net regulatory liabilities	$ 986,000,000	$ 986,000,000	$ 947,000,000			$ 986,000,000
CECONY
Public Utilities, General Disclosures [Line Items]
Cost reconciliations, deferred net regulatory liabilities	940,000,000	940,000,000	899,000,000			940,000,000
CECONY | Electric
Public Utilities, General Disclosures [Line Items]
Deferred revenues	101,000,000	101,000,000	98,000,000	$ 146,000,000		101,000,000
Negative revenue adjustments		0	0	5,000,000
Cost reconciliations, deferred net regulatory liabilities	68,000,000	68,000,000	26,000,000	57,000,000		$ 68,000,000
Deferred regulatory asset		9,000,000	17,000,000	6,000,000
Earnings sharing, threshold limit		6,500,000	44,400,000	$ 0
Common equity ratio (percent)						48.00%
Base rate change deferral regulatory liability impact	0	$ 0	$ 30,000,000			$ 0
Increase in gas base rate due to expiration of temporary credit under the prior rate plan	$ 48,000,000
Deferrals for property taxes limitation from rates (percent)		90.00%
Recovery deferral (percentage)	80.00%	80.00%				80.00%
Maximum deferral (percentage)	30.00%	30.00%				30.00%
CECONY | Electric | Deferred storm costs
Public Utilities, General Disclosures [Line Items]
Amortization of regulatory asset		$ 107,000,000
Decrease in recoverable property damage costs		4,000,000
CECONY | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Amortization to income of net regulatory (assets) and liabilities		123,000,000
Authorized return on common equity (percent)					9.00%
Earnings sharing (percentage)					9.50%
Common equity ratio (percent)					48.00%
Recovery or refund of energy costs, deferral period					10 years
CECONY | Electric | Scenario, Forecast | NYSPSC
Public Utilities, General Disclosures [Line Items]
Base rate changes					$ 199,000,000
CECONY | Electric | Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes	$ (76,200,000)	$ (76,200,000)				$ (76,200,000)
Amortization to income of net regulatory (assets) and liabilities						(37,000,000)
Retention of annual transmission congestion revenues						90,000,000
Average rate base						$ 17,323,000,000
Weighted average cost of capital (after-tax) (percent)						7.05%
Authorized return on common equity (percent)						9.20%
Earnings sharing (percentage)	9.80%	9.80%				9.80%
Cost of long-term debt (percent)	5.17%	5.17%				5.17%
Deferral, annual maximum (not more than) (percent)		0.05%
CECONY | Electric | Year 1 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)						$ 400,000,000
CECONY | Electric | Year 1 | Transmission and distribution
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset						16,869,000,000
CECONY | Electric | Year 1 | Storm hardening
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset						89,000,000
CECONY | Electric | Year 1 | Other
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset						2,034,000,000
CECONY | Electric | Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes					195,000,000
Amortization to income of net regulatory (assets) and liabilities					84,000,000
Retention of annual transmission congestion revenues					75,000,000
Potential earnings adjustment mechanism incentives					28,000,000
Potential penalties (annually)					376,000,000
Average rate base					$ 18,902,000,000
Weighted average cost of capital (after-tax) (percent)					6.82%
Cost of long-term debt (percent)					4.93%
Recovery of energy efficiency and savings program costs					$ 20,500,000
CECONY | Electric | Year 1 | Scenario, Forecast | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset					21,689,000,000
CECONY | Electric | Year 1 | Scenario, Forecast | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset					126,000,000
CECONY | Electric | Year 2
Public Utilities, General Disclosures [Line Items]
Base rate changes	$ 124,000,000	$ 124,000,000				124,000,000
Amortization to income of net regulatory (assets) and liabilities						(37,000,000)
Retention of annual transmission congestion revenues						90,000,000
Average rate base						$ 18,113,000,000
Weighted average cost of capital (after-tax) (percent)						7.08%
Authorized return on common equity (percent)						9.20%
Earnings sharing (percentage)	9.80%	9.80%				9.80%
Cost of long-term debt (percent)	5.23%	5.23%				5.23%
Deferral, annual maximum (not more than) (percent)		0.075%
CECONY | Electric | Year 2 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)						$ 400,000,000
CECONY | Electric | Year 2 | Transmission and distribution
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset						17,401,000,000
CECONY | Electric | Year 2 | Storm hardening
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset						177,000,000
CECONY | Electric | Year 2 | Other
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset						2,102,000,000
CECONY | Electric | Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes					155,000,000
Amortization to income of net regulatory (assets) and liabilities					83,000,000
Retention of annual transmission congestion revenues					75,000,000
Potential earnings adjustment mechanism incentives					47,000,000
Potential penalties (annually)					383,000,000
Average rate base					$ 19,530,000,000
Weighted average cost of capital (after-tax) (percent)					6.80%
Cost of long-term debt (percent)					4.88%
Recovery of energy efficiency and savings program costs					$ 49,000,000
CECONY | Electric | Year 2 | Scenario, Forecast | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset					22,338,000,000
CECONY | Electric | Year 2 | Scenario, Forecast | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset					257,000,000
CECONY | Electric | Year 3
Public Utilities, General Disclosures [Line Items]
Base rate changes	$ 0	$ 0				0
Amortization to income of net regulatory (assets) and liabilities						123,000,000
Retention of annual transmission congestion revenues						90,000,000
Average rate base						$ 18,282,000,000
Weighted average cost of capital (after-tax) (percent)						6.91%
Authorized return on common equity (percent)						9.00%
Earnings sharing (percentage)	9.60%	9.60%				9.60%
Cost of long-term debt (percent)	5.09%	5.09%				5.09%
Deferral, annual maximum (not more than) (percent)		0.10%
CECONY | Electric | Year 3 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)						$ 400,000,000
CECONY | Electric | Year 3 | Transmission and distribution
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset						17,929,000,000
CECONY | Electric | Year 3 | Storm hardening
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset						268,000,000
CECONY | Electric | Year 3 | Other
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset						$ 2,069,000,000
CECONY | Electric | Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes					155,000,000
Amortization to income of net regulatory (assets) and liabilities					69,000,000
Retention of annual transmission congestion revenues					75,000,000
Potential earnings adjustment mechanism incentives					64,000,000
Potential penalties (annually)					395,000,000
Average rate base					$ 20,277,000,000
Weighted average cost of capital (after-tax) (percent)					6.73%
Cost of long-term debt (percent)					4.74%
Recovery of energy efficiency and savings program costs					$ 107,500,000
CECONY | Electric | Year 3 | Scenario, Forecast | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset					23,002,000,000
CECONY | Electric | Year 3 | Scenario, Forecast | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Deferred regulatory asset					$ 415,000,000

Regulatory Matters - Summary 65

Regulatory Matters - Summary of Utilities Rate Plans (CECONY-Gas) (Details) - USD ($)	9 Months Ended	12 Months Ended			36 Months Ended
	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2019	Dec. 31, 2016
Public Utilities, General Disclosures [Line Items]
Cost reconciliations, deferred net regulatory liabilities		$ 986,000,000	$ 947,000,000			$ 986,000,000
CECONY
Public Utilities, General Disclosures [Line Items]
Cost reconciliations, deferred net regulatory liabilities		940,000,000	899,000,000			940,000,000
CECONY | Gas
Public Utilities, General Disclosures [Line Items]
Amount of revenues retained		65,000,000	66,000,000	$ 70,000,000		$ 65,000,000
Percentage of revenue reserve						15.00%
Deferred revenues		71,000,000	54,000,000	28,000,000		$ 71,000,000
Potential penalties (annually)		56,000,000	44,000,000	33,000,000
Negative revenue adjustments		0	0	0
Cost reconciliations, deferred net regulatory liabilities		$ 32,000,000	11,000,000	38,000,000		$ 32,000,000
Net utility plant reconciliations			1,000,000
Earnings sharing (percentage)		9.90%				9.90%
Earnings sharing, threshold limit		$ 0	$ 0	$ 0
Common equity ratio (percent)						48.00%
Base rate change deferral regulatory liability impact		$ 32,000,000				$ 32,000,000
Increase in gas base rate due to expiration of temporary credit under the prior rate plan	$ 41,000,000
Difference in property taxes (percent)		90.00%
Deferral, annual maximum (not more than) (percent)		0.10%
CECONY | Gas | Maximum
Public Utilities, General Disclosures [Line Items]
Amount of revenues retained		$ 65,000,000				65,000,000
CECONY | Gas | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Percentage of revenue reserve					15.00%
Earnings sharing (percentage)					9.50%
Common equity ratio (percent)					48.00%
CECONY | Gas | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Amount of revenues retained					$ 65,000,000
CECONY | Gas | Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes						(54,600,000)
Amortization to income of net regulatory (assets) and liabilities						4,000,000
Average rate base						$ 3,521,000,000
Weighted average cost of capital (after-tax) (percent)						7.10%
Authorized return on common equity (percent)						9.30%
Cost of long-term debt (percent)		5.17%				5.17%
CECONY | Gas | Year 1 | Gas delivery
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations						$ 3,899,000,000
CECONY | Gas | Year 1 | Storm hardening
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations						3,000,000
CECONY | Gas | Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes					(5,000,000)
Amortization to income of net regulatory (assets) and liabilities					39,000,000
Potential incentives if performance targets are met					7,000,000
Potential penalties (annually)					68,000,000
Average rate base					$ 4,841,000,000
Weighted average cost of capital (after-tax) (percent)					6.82%
Authorized return on common equity (percent)					9.00%
Cost of long-term debt (percent)					4.93%
CECONY | Gas | Year 1 | Scenario, Forecast | Gas excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					$ 5,844,000,000
CECONY | Gas | Year 1 | Scenario, Forecast | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					27,000,000
CECONY | Gas | Year 2
Public Utilities, General Disclosures [Line Items]
Base rate changes						38,600,000
Amortization to income of net regulatory (assets) and liabilities						4,000,000
Average rate base						$ 3,863,000,000
Weighted average cost of capital (after-tax) (percent)						7.13%
Cost of long-term debt (percent)		5.23%				5.23%
CECONY | Gas | Year 2 | Gas delivery
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations						$ 4,258,000,000
CECONY | Gas | Year 2 | Storm hardening
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations						8,000,000
CECONY | Gas | Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes					92,000,000
Amortization to income of net regulatory (assets) and liabilities					37,000,000
Potential incentives if performance targets are met					8,000,000
Potential penalties (annually)					75,000,000
Average rate base					$ 5,395,000,000
Weighted average cost of capital (after-tax) (percent)					6.80%
Cost of long-term debt (percent)					4.88%
CECONY | Gas | Year 2 | Scenario, Forecast | Gas excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					$ 6,512,000,000
CECONY | Gas | Year 2 | Scenario, Forecast | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					57,000,000
CECONY | Gas | Year 3
Public Utilities, General Disclosures [Line Items]
Base rate changes						56,800,000
Amortization to income of net regulatory (assets) and liabilities						4,000,000
Average rate base						$ 4,236,000,000
Weighted average cost of capital (after-tax) (percent)						7.21%
Cost of long-term debt (percent)		5.39%				5.39%
CECONY | Gas | Year 3 | Gas delivery
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations						$ 4,698,000,000
CECONY | Gas | Year 3 | Storm hardening
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations						$ 30,000,000
CECONY | Gas | Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes					90,000,000
Amortization to income of net regulatory (assets) and liabilities					36,000,000
Potential incentives if performance targets are met					8,000,000
Potential penalties (annually)					83,000,000
Average rate base					$ 6,005,000,000
Weighted average cost of capital (after-tax) (percent)					6.73%
Cost of long-term debt (percent)					4.74%
CECONY | Gas | Year 3 | Scenario, Forecast | Gas excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					$ 7,177,000,000
CECONY | Gas | Year 3 | Scenario, Forecast | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					$ 100,000,000

Regulatory Matters - Summary 66

Regulatory Matters - Summary of Utilities Rate Plans (CECONY-Steam) (Details) - USD ($)	12 Months Ended			36 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016
Public Utilities, General Disclosures [Line Items]
Cost reconciliation, deferred net regulatory liabilities	$ 986,000,000	$ 947,000,000		$ 986,000,000
Cost reconciliations, deferred net regulatory assets	822,000,000	836,000,000		822,000,000
CECONY
Public Utilities, General Disclosures [Line Items]
Cost reconciliation, deferred net regulatory liabilities	940,000,000	899,000,000		940,000,000
Cost reconciliations, deferred net regulatory assets	728,000,000	752,000,000		728,000,000
CECONY | Steam
Public Utilities, General Disclosures [Line Items]
Negative revenue adjustments	0	0	$ 0
Cost reconciliation, deferred net regulatory liabilities	$ 8,000,000		42,000,000	$ 8,000,000
Cost reconciliations, deferred net regulatory assets		17,000,000
Deferred regulatory liability (reduction)			100,000
Authorized return on common equity (percent)				9.30%
Earnings sharing (percentage)	9.90%			9.90%
Earnings sharing, threshold limit	$ 7,800,000	$ 11,500,000	$ 0
Common equity ratio (percent)				48.00%
Other regulatory liabilities	$ 8,000,000			$ 8,000,000
Difference in property taxes (percent)	90.00%
Deferral, annual maximum (not more than) (percent)	0.10%
CECONY | Steam | Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes				(22,400,000)
Amortization to income of net regulatory (assets) and liabilities				37,000,000
Average rate base				$ 1,511,000,000
Weighted average cost of capital (after-tax) (percent)				7.10%
Cost of long-term debt (percent)	5.17%			5.17%
CECONY | Steam | Year 1 | Production
Public Utilities, General Disclosures [Line Items]
Deferred regulatory liability (reduction)				$ 1,752,000,000
CECONY | Steam | Year 1 | Distribution
Public Utilities, General Disclosures [Line Items]
Deferred regulatory liability (reduction)				6,000,000
CECONY | Steam | Year 1 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)				1,000,000
CECONY | Steam | Year 2
Public Utilities, General Disclosures [Line Items]
Base rate changes				19,800,000
Amortization to income of net regulatory (assets) and liabilities				37,000,000
Average rate base				$ 1,547,000,000
Weighted average cost of capital (after-tax) (percent)				7.13%
Cost of long-term debt (percent)	5.23%			5.23%
CECONY | Steam | Year 2 | Production
Public Utilities, General Disclosures [Line Items]
Deferred regulatory liability (reduction)				$ 1,732,000,000
CECONY | Steam | Year 2 | Distribution
Public Utilities, General Disclosures [Line Items]
Deferred regulatory liability (reduction)				11,000,000
CECONY | Steam | Year 2 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)				1,000,000
CECONY | Steam | Year 3
Public Utilities, General Disclosures [Line Items]
Base rate changes				20,300,000
Amortization to income of net regulatory (assets) and liabilities				37,000,000
Average rate base				$ 1,604,000,000
Weighted average cost of capital (after-tax) (percent)				7.21%
Cost of long-term debt (percent)	5.39%			5.39%
CECONY | Steam | Year 3 | Production
Public Utilities, General Disclosures [Line Items]
Deferred regulatory liability (reduction)				$ 1,720,000,000
CECONY | Steam | Year 3 | Distribution
Public Utilities, General Disclosures [Line Items]
Deferred regulatory liability (reduction)				25,000,000
CECONY | Steam | Year 3 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)				1,000,000
CECONY | Steam | Year 4
Public Utilities, General Disclosures [Line Items]
Base rate changes				$ 0

Regulatory Matters - Summary 67

Regulatory Matters - Summary of Utilities Rate Plans (O&R New York-Electric) (Details) - O&R - Electric - USD ($)	12 Months Ended					24 Months Ended	36 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 31, 2017	Jun. 30, 2015
Public Utilities, General Disclosures [Line Items]
Deferred revenues	$ 6,300,000	$ 6,300,000	$ (3,400,000)	$ 3,200,000	$ 2,600,000
Negative revenue adjustments	0	1,250,000	0	0	0
Deferral of net increase (decrease) to regulatory assets	7,400,000	300,000	(200,000)	4,100,000	7,800,000
Deferred regulatory liability (reduction)	(1,900,000)	$ 2,200,000	(2,300,000)	$ (1,100,000)	$ 4,200,000
Earnings sharing, threshold limit	$ 6,100,000		$ 1,000,000
Common equity ratio (percent)							48.00%
Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Authorized return on common equity (percent)						9.00%
Earnings sharing (percentage)						9.60%
Common equity ratio (percent)						48.00%
Deferred storm and property reserve deficiency, noncurrent						$ 59,300,000
Deferred storm and property reserve deficiency, recovery period						5 years
Deferred storm and property reserve deficiency not recovered						$ 1,000,000
Scenario, Forecast | Property Tax and Interest Rate Reconciliations
Public Utilities, General Disclosures [Line Items]
Regulatory assets not recoverable						4,000,000
Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes							$ 19,400,000
Amortization to income of net regulatory (assets) and liabilities							(32,200,000)
Deferred regulatory liability (reduction)							678,000,000
Average rate base							$ 671,000,000
Weighted average cost of capital (after-tax) (percent)							7.61%
Authorized return on common equity (percent)							9.40%
Cost of long-term debt (percent)							6.07%
Year 1 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)							$ 3,000,000
Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes						9,300,000
Amortization to income of net regulatory (assets) and liabilities						(8,500,000)
Deferred regulatory liability (reduction)						928,000,000
Average rate base						$ 763,000,000
Weighted average cost of capital (after-tax) (percent)						7.10%
Cost of long-term debt (percent)						5.42%
Deferred storm and property reserve deficiency, noncurrent						$ 11,850,000
Rate exclusion amount with balance below regulatory threshold						1,000,000
Year 1 | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)						4,000,000
Year 2
Public Utilities, General Disclosures [Line Items]
Base rate changes							8,800,000
Amortization to income of net regulatory (assets) and liabilities							(32,200,000)
Deferred regulatory liability (reduction)							704,000,000
Average rate base							$ 708,000,000
Weighted average cost of capital (after-tax) (percent)							7.65%
Authorized return on common equity (percent)							9.50%
Cost of long-term debt (percent)							6.07%
Year 2 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)							$ 3,000,000
Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes						8,800,000
Amortization to income of net regulatory (assets) and liabilities						(9,400,000)
Deferred regulatory liability (reduction)						970,000,000
Average rate base						$ 805,000,000
Weighted average cost of capital (after-tax) (percent)						7.06%
Cost of long-term debt (percent)						5.35%
Deferred storm and property reserve deficiency, noncurrent						$ 11,850,000
Rate exclusion amount with balance below regulatory threshold						9,000,000
Year 2 | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)						$ 4,000,000
Year 3
Public Utilities, General Disclosures [Line Items]
Base rate changes							15,200,000
Amortization to income of net regulatory (assets) and liabilities							(32,200,000)
Deferred regulatory liability (reduction)							753,000,000
Average rate base							$ 759,000,000
Weighted average cost of capital (after-tax) (percent)							7.48%
Authorized return on common equity (percent)							9.60%
Cost of long-term debt (percent)							5.64%
Year 3 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)							$ 3,000,000

Regulatory Matters - Summary 68

Regulatory Matters - Summary of Utilities Rate Plans (O&R New York-Gas) (Details) - USD ($)	12 Months Ended					36 Months Ended	62 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 31, 2018	Dec. 31, 2014
Public Utilities, General Disclosures [Line Items]
Cost reconciliations, deferred net regulatory assets	$ 822,000,000	$ 836,000,000
O&R | Gas
Public Utilities, General Disclosures [Line Items]
Deferred revenues	6,200,000	(800,000)	$ (100,000)	$ 700,000	$ 4,700,000		$ (100,000)
Negative revenue adjustments	0	0	0	0	0
Cost reconciliations, deferred net regulatory assets	6,600,000	4,500,000	8,300,000	8,300,000	700,000		$ 8,300,000
Net utility plant reconciliations		$ 0	0	0	700,000
Weighted average cost of capital (after-tax) (percent)							8.49%
Authorized return on common equity (percent)							10.40%
Earnings sharing, threshold limit	$ 4,000,000		$ 0	$ 0	$ 0
Cost of long-term debt (percent)			6.81%				6.81%
Common equity ratio (percent)							48.00%
O&R | Gas | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Authorized return on common equity (percent)						9.00%
Common equity ratio (percent)						48.00%
O&R | Gas | Scenario, Forecast | Property Tax and Interest Rate Reconciliations
Public Utilities, General Disclosures [Line Items]
Regulatory assets not recoverable						$ 14,000,000
O&R | Gas | Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes							$ 9,000,000
Amortization to income of net regulatory (assets) and liabilities							(2,000,000)
Average rate base							$ 280,000,000
Earnings sharing (percentage)			11.40%				11.40%
O&R | Gas | Year 1 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)							$ 1,400,000
O&R | Gas | Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes						16,400,000
Amortization to income of net regulatory (assets) and liabilities						(1,700,000)
Average rate base						$ 366,000,000
Weighted average cost of capital (after-tax) (percent)						7.10%
Earnings sharing (percentage)						9.60%
Cost of long-term debt (percent)						5.42%
Rate exclusion amount with balance below regulatory threshold						$ 500,000
O&R | Gas | Year 1 | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)						3,700,000
Net utility plant reconciliations						492,000,000
O&R | Gas | Year 2
Public Utilities, General Disclosures [Line Items]
Base rate changes							9,000,000
Amortization to income of net regulatory (assets) and liabilities							(2,000,000)
Average rate base							$ 296,000,000
Earnings sharing (percentage)			11.40%				11.40%
O&R | Gas | Year 2 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)							$ 1,400,000
O&R | Gas | Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes						16,400,000
Amortization to income of net regulatory (assets) and liabilities						(2,100,000)
Average rate base						$ 391,000,000
Weighted average cost of capital (after-tax) (percent)						7.06%
Earnings sharing (percentage)						9.60%
Cost of long-term debt (percent)						5.35%
Rate exclusion amount with balance below regulatory threshold						$ 4,200,000
O&R | Gas | Year 2 | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)						4,700,000
Net utility plant reconciliations						518,000,000
O&R | Gas | Year 3
Public Utilities, General Disclosures [Line Items]
Base rate changes							4,600,000
Base rate change through surcharge							4,300,000
Amortization to income of net regulatory (assets) and liabilities							(2,000,000)
Average rate base							$ 309,000,000
Earnings sharing (percentage)			11.40%				11.40%
O&R | Gas | Year 3 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)							$ 1,400,000
O&R | Gas | Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes						5,800,000
Base rate change through surcharge						10,600,000
Amortization to income of net regulatory (assets) and liabilities						(2,500,000)
Average rate base						$ 417,000,000
Weighted average cost of capital (after-tax) (percent)						7.06%
Earnings sharing (percentage)						9.60%
Cost of long-term debt (percent)						5.35%
Rate exclusion amount with balance below regulatory threshold						$ 7,200,000
O&R | Gas | Year 3 | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)						5,800,000
Net utility plant reconciliations						$ 546,000,000
O&R | Gas | Year 4
Public Utilities, General Disclosures [Line Items]
Base rate change through surcharge							0
O&R | Gas | Year 5
Public Utilities, General Disclosures [Line Items]
Base rate change through surcharge							$ 0

Regulatory Matters - Summary 69

Regulatory Matters - Summary of Utilities Rate Plans (Rockland Electric Company (RECO)) (Details) - Rockland Electric Company (RECO) - USD ($) $ in Millions	1 Months Ended	12 Months Ended	51 Months Ended
	Jan. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Public Utilities, General Disclosures [Line Items]
Average rate base		$ 172.2	$ 148.6
Weighted average cost of capital (after-tax) (percent)		7.83%	8.21%
Authorized return on common equity (percent)		9.75%	10.30%
Cost of long-term debt (percent)		5.89%	6.16%
Common equity ratio (percent)		50.00%	50.00%
Electric
Public Utilities, General Disclosures [Line Items]
RECO plan period (years)	3 years
RECO plan electric system storm hardening amount	$ 15.7
Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes		$ 13	$ 9.8
Amortization to income of net regulatory (assets) and liabilities		0.4	(3.9)
Deferred major storm costs		(25.6)	(4.9)
Year 2
Public Utilities, General Disclosures [Line Items]
Amortization to income of net regulatory (assets) and liabilities		0.4	(3.9)
Deferred major storm costs		(25.6)	(4.9)
Year 3
Public Utilities, General Disclosures [Line Items]
Amortization to income of net regulatory (assets) and liabilities		0.4	(3.9)
Deferred major storm costs		(25.6)	(4.9)
Year 4
Public Utilities, General Disclosures [Line Items]
Amortization to income of net regulatory (assets) and liabilities			(3.9)
Deferred major storm costs		$ (25.6)	(4.9)
Year 5
Public Utilities, General Disclosures [Line Items]
Deferred major storm costs			$ (4.9)

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended			12 Months Ended
	Feb. 16, 2017	Jan. 31, 2017	Oct. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities				$ 1,905	$ 1,977
FERC | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested return on equity (percent)		10.70%
Requested equity capital structure (percent)		48.00%
Rockland Electric Company (RECO) | NJBPU | Subsequent Event | Rockland Electric Company (RECO) | Electric
Public Utilities, General Disclosures [Line Items]
Interim rate increase, amount	$ 1.7
Requested return on equity (percent)	9.60%
Requested equity capital structure (percent)	49.70%
Rockland Electric Company (RECO) | FERC
Public Utilities, General Disclosures [Line Items]
Requested rate increase, amount				11.8
Rockland Electric Company (RECO) | FERC | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested rate increase, amount		$ 19.7
CECONY
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities				1,712	$ 1,789
CECONY | June 2014 Plastic Fusion Proceeding
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities				$ 27
CECONY | Subsequent Event | June 2014 Plastic Fusion Proceeding
Public Utilities, General Disclosures [Line Items]
Loss from settlement	$ 126
CECONY | NYSPSC
Public Utilities, General Disclosures [Line Items]
Risk assessment and remediation plan, period			3 years

Regulatory Matters - Regulatory

Regulatory Matters - Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	$ 1,905	$ 1,977
Regulatory liabilities—current	128	115
Total Regulatory Liabilities	2,033	2,092
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	7,024	8,096
Regulatory assets – current	100	132
Total Regulatory Assets	7,124	8,228
Allowance for cost of removal less salvage
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	755	676
Pension and other postretirement benefit deferrals
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	193	76
Property tax reconciliation
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	178	303
Net unbilled revenue deferrals
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	145	109
Prudence proceeding
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	95	99
Carrying charges on repair allowance and bonus depreciation
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	68	49
New York State income tax rate change
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	61	75
Unrecognized other postretirement costs
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	60	28
Variable-rate tax-exempt debt - cost rate reconciliation
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	55	70
Base rate change deferrals
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	40	128
Earnings sharing - electric, gas and steam
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	39	80
Net utility plant reconciliations
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	16	32
Property tax refunds
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	1	44
World Trade Center settlement proceeds
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	0	21
Other
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	199	187
Revenue decoupling mechanism
Regulatory Liabilities [Line Items]
Regulatory liabilities—current	71	45
Refundable energy costs
Regulatory Liabilities [Line Items]
Regulatory liabilities—current	29	64
Deferred derivative gains
Regulatory Liabilities [Line Items]
Regulatory liabilities—current	28	6
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	2,874	3,876
Future income tax
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	2,439	2,350
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	823	904
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	295	253
Deferred storm costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	56	185
Deferred derivative losses
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	48	50
Unamortized loss on reacquired debt
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	43	50
Recoverable energy costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	42	16
Regulatory assets – current	9	19
Pension and other postretirement benefits deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	38	45
O&R property tax reconciliation
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	37	46
Surcharge for New York State assessment
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	28	44
Preferred stock redemption
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	25	26
Net electric deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	24	44
O&R transition bond charges
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	15	21
Workers’ compensation
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	13	11
Other
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	224	175
Deferred derivative losses
Regulatory Assets [Line Items]
Regulatory assets – current	91	113
CECONY
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	1,712	1,789
Regulatory liabilities—current	90	84
Total Regulatory Liabilities	1,802	1,873
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	6,473	7,482
Regulatory assets – current	90	121
Total Regulatory Assets	6,563	7,603
CECONY | Allowance for cost of removal less salvage
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	641	570
CECONY | Pension and other postretirement benefit deferrals
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	162	46
CECONY | Property tax reconciliation
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	178	303
CECONY | Net unbilled revenue deferrals
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	145	109
CECONY | Prudence proceeding
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	95	99
CECONY | Carrying charges on repair allowance and bonus depreciation
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	67	48
CECONY | New York State income tax rate change
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	60	72
CECONY | Unrecognized other postretirement costs
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	60	28
CECONY | Variable-rate tax-exempt debt - cost rate reconciliation
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	48	60
CECONY | Base rate change deferrals
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	40	128
CECONY | Earnings sharing - electric, gas and steam
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	28	80
CECONY | Net utility plant reconciliations
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	15	31
CECONY | Property tax refunds
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	1	44
CECONY | World Trade Center settlement proceeds
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	0	21
CECONY | Other
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	172	150
CECONY | Revenue decoupling mechanism
Regulatory Liabilities [Line Items]
Regulatory liabilities—current	61	45
CECONY | Refundable energy costs
Regulatory Liabilities [Line Items]
Regulatory liabilities—current	5	33
CECONY | Deferred derivative gains
Regulatory Liabilities [Line Items]
Regulatory liabilities—current	24	6
CECONY | Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	2,730	3,697
CECONY | Future income tax
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	2,325	2,232
CECONY | Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	711	800
CECONY | Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	280	240
CECONY | Deferred storm costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	3	110
CECONY | Deferred derivative losses
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	42	46
CECONY | Unamortized loss on reacquired debt
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	41	48
CECONY | Recoverable energy costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	38	15
Regulatory assets – current	4	18
CECONY | Pension and other postretirement benefits deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	7	16
CECONY | O&R property tax reconciliation
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	0	0
CECONY | Surcharge for New York State assessment
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	26	40
CECONY | Preferred stock redemption
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	25	26
CECONY | Net electric deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	24	44
CECONY | O&R transition bond charges
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	0	0
CECONY | Workers’ compensation
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	13	11
CECONY | Other
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	208	157
CECONY | Deferred derivative losses
Regulatory Assets [Line Items]
Regulatory assets – current	$ 86	$ 103

Capitalization - Additional Inf

Capitalization - Additional Information (Details)		12 Months Ended
		Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)
Schedule of Capitalization [Line Items]
Percentage limitation for income available for dividends (not more than)		100.00%
Rolling average calculation of income available for dividends (years)		2 years
Long-term debt, fair value		$ 16,093,000,000	$ 13,856,000,000
Long-term debt		14,774,000,000	12,745,000,000
Non-recourse debt		$ 845,000,000	339,000,000
Ratio of consolidated debt to consolidated total capital		0.51
Maximum
Schedule of Capitalization [Line Items]
Ratio of consolidated debt to consolidated total capital		0.65
Transition Bonds, Issued in 2004
Schedule of Capitalization [Line Items]
Long-term debt		$ 11,000,000	15,000,000
Level 2
Schedule of Capitalization [Line Items]
Long-term debt, fair value		15,457,000,000
Level 3
Schedule of Capitalization [Line Items]
Long-term debt, fair value		636,000,000
Tax-Exempt Debt
Schedule of Capitalization [Line Items]
Long-term debt	[1]	1,086,000,000	1,086,000,000
Notes
Schedule of Capitalization [Line Items]
Covenant principal balance amount limit		$ 100,000,000
Notes | Maximum
Schedule of Capitalization [Line Items]
Ratio of consolidated debt to consolidated total capital		0.675
Term Loan
Schedule of Capitalization [Line Items]
Covenant principal balance amount limit		$ 150,000,000
Term Loan | Maximum
Schedule of Capitalization [Line Items]
Ratio of consolidated debt to consolidated total capital		0.65
CECONY
Schedule of Capitalization [Line Items]
Common stock shares, outstanding | shares		21,976,200
Long-term debt, fair value		$ 13,268,000,000	12,427,000,000
Long-term debt		$ 12,073,000,000	11,437,000,000
Ratio of consolidated debt to consolidated total capital		0.52
CECONY | Maximum
Schedule of Capitalization [Line Items]
Ratio of consolidated debt to consolidated total capital		0.65
Covenant principal balance amount limit		$ 100,000,000
CECONY | Minimum
Schedule of Capitalization [Line Items]
Covenant principal balance amount limit		150,000,000
CECONY | Level 2
Schedule of Capitalization [Line Items]
Long-term debt, fair value		12,632,000,000
CECONY | Level 3
Schedule of Capitalization [Line Items]
Long-term debt, fair value		636,000,000
CECONY | Tax-Exempt Debt
Schedule of Capitalization [Line Items]
Tax-exempt debt issued, value		450,000,000
Long-term debt		1,086,000,000	$ 1,086,000,000
CECONY | Tax-Exempt Debt | Level 3
Schedule of Capitalization [Line Items]
Long-term debt		$ 636,000,000
[1]	Rates are to be reset weekly or by auction held every 35 days; December 31, 2016 rates shown.

Capitalization - Schedule of Lo

Capitalization - Schedule of Long-Term Debt Maturities (Details) $ in Millions	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
2,017	$ 39
2,018	1,688
2,019	574
2,020	388
2,021	540
CECONY
Debt Instrument [Line Items]
2,017	0
2,018	1,200
2,019	475
2,020	350
2,021	$ 0

Capitalization - Carrying Amoun

Capitalization - Carrying Amounts and Fair Values of Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Carrying Amount	$ 14,774	$ 12,745
Fair Value	16,093	13,856
CECONY
Debt Instrument [Line Items]
Carrying Amount	12,073	11,437
Fair Value	$ 13,268	$ 12,427

Short-Term Borrowing (Details)

Short-Term Borrowing (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Short-term Debt [Line Items]
Commercial paper, outstanding	$ 1,054,000,000	$ 1,529,000,000
Weighted average interest rate	1.00%	0.70%
Loans outstanding under credit agreement	$ 0	$ 0
Letters of credit outstanding under the Credit Agreement	$ 2,000,000	15,000,000
Ratio of consolidated debt to consolidated total capital	0.51
Minimum percentage of liens on assets	5.00%
Maximum
Short-term Debt [Line Items]
Ratio of consolidated debt to consolidated total capital	0.65
Revolving Credit
Short-term Debt [Line Items]
Maximum borrowing capacity	$ 1,500,000,000
Current amount available	1,000,000,000
Letters of Credit
Short-term Debt [Line Items]
Maximum borrowing capacity	1,200,000,000
CECONY
Short-term Debt [Line Items]
Commercial paper, outstanding	$ 600,000,000	$ 1,033,000,000
Weighted average interest rate	1.00%	0.70%
Letters of credit outstanding under the Credit Agreement	$ 2,000,000
Ratio of consolidated debt to consolidated total capital	0.52
CECONY | Maximum
Short-term Debt [Line Items]
Ratio of consolidated debt to consolidated total capital	0.65
CECONY | Revolving Credit
Short-term Debt [Line Items]
Maximum borrowing capacity	$ 2,250,000,000

Pension Benefits - Total Period

Pension Benefits - Total Periodic Benefit Costs (Details) - Pension Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	$ 275	$ 297	$ 227
Interest cost on projected benefit obligation	596	575	572
Expected return on plan assets	(947)	(886)	(832)
Recognition of net actuarial loss	596	775	618
Recognition of prior service costs	4	4	4
NET PERIODIC BENEFIT COST	524	765	589
Amortization of regulatory asset	0	1	2
TOTAL PERIODIC BENEFIT COST	524	766	591
Cost capitalized	(214)	(301)	(225)
Reconciliation to rate level	54	(74)	118
Cost charged to operating expenses	364	391	484
CECONY
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	258	279	211
Interest cost on projected benefit obligation	559	538	536
Expected return on plan assets	(898)	(840)	(789)
Recognition of net actuarial loss	565	734	586
Recognition of prior service costs	2	2	2
NET PERIODIC BENEFIT COST	486	713	546
Amortization of regulatory asset	0	1	2
TOTAL PERIODIC BENEFIT COST	486	714	548
Cost capitalized	(203)	(285)	(212)
Reconciliation to rate level	58	(74)	108
Cost charged to operating expenses	$ 341	355	444
Increase in CECONY's pension obligation		$ 45	$ 45

Pension Benefits - Schedule of

Pension Benefits - Schedule of Funded Status (Details) - Pension Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CHANGE IN PROJECTED BENEFIT OBLIGATION
Projected benefit obligation at beginning of year	$ 14,377	$ 15,081	$ 12,197
Service cost – excluding administrative expenses	271	293	221
Interest cost on projected benefit obligation	596	575	572
Net actuarial (gain)/loss	(302)	(996)	2,641
Plan amendments	(256)	0	6
Benefits paid	(591)	(576)	(556)
PROJECTED BENEFIT OBLIGATION AT END OF YEAR	14,095	14,377	15,081
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	11,759	11,495	10,755
Actual return on plan assets	829	126	752
Employer contributions	508	750	578
Benefits paid	(591)	(576)	(556)
Administrative expenses	(33)	(36)	(34)
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	12,472	11,759	11,495
FUNDED STATUS	(1,623)	(2,618)	(3,586)
Unrecognized net loss	3,157	3,909	4,888
Unrecognized prior service costs	(244)	16	20
Accumulated benefit obligation	12,655	12,909	13,454
CECONY
CHANGE IN PROJECTED BENEFIT OBLIGATION
Projected benefit obligation at beginning of year	13,482	14,137	11,429
Service cost – excluding administrative expenses	254	274	206
Interest cost on projected benefit obligation	559	538	536
Net actuarial (gain)/loss	(282)	(931)	2,484
Plan amendments	(259)	0	0
Benefits paid	(551)	(536)	(518)
PROJECTED BENEFIT OBLIGATION AT END OF YEAR	13,203	13,482	14,137
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	11,141	10,897	10,197
Actual return on plan assets	787	118	715
Employer contributions	469	697	535
Benefits paid	(551)	(536)	(518)
Administrative expenses	(31)	(35)	(32)
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	11,815	11,141	10,897
FUNDED STATUS	(1,388)	(2,341)	(3,240)
Unrecognized net loss	2,995	3,704	4,616
Unrecognized prior service costs	(258)	3	4
Accumulated benefit obligation	$ 11,806	$ 12,055	$ 12,553

Pension Benefits - Additional I

Pension Benefits - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Pension liability	$ 995,000,000
Investments value	273,000,000	$ 243,000,000
Other Nonqualified Supplemental Defined Benefit Pension
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	303,000,000	285,000,000
CECONY
Defined Benefit Plan Disclosure [Line Items]
Pension liability	953,000,000
Investments value	246,000,000	221,000,000
CECONY | Other Nonqualified Supplemental Defined Benefit Pension
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	268,000,000	249,000,000
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Decrease to regulatory assets	1,002,000,000
Charge to OCI	5,000,000
Net loss estimated to be amortized	579,000,000
Prior service cost estimated to be amortized	(16,000,000)
Accumulated benefit obligation	12,655,000,000	12,909,000,000	$ 13,454,000,000
Defined benefit plan, bond amount (excess of)	50,000,000
Estimated future employer contributions	$ 423,000,000
Increase in pension benefit obligation			800,000,000
Pension Benefits | Minimum
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, percent of bond original price	50.00%
Defined benefit plan, bond yield (percent)	1.00%
Pension Benefits | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, percent of bond original price	200.00%
Defined benefit plan, bond yield (percent)	20.00%
Pension Benefits | CECONY
Defined Benefit Plan Disclosure [Line Items]
Decrease to regulatory assets	$ 967,000,000
Charge to OCI	1,000,000
Net loss estimated to be amortized	548,000,000
Prior service cost estimated to be amortized	(18,000,000)
Accumulated benefit obligation	11,806,000,000	$ 12,055,000,000	$ 12,553,000,000
Estimated future employer contributions	$ 388,000,000

Pension Benefits - Schedule o79

Pension Benefits - Schedule of Assumptions (Details) - Pension Benefits	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Discount rate, benefit obligations	4.25%	4.25%	3.90%
Discount rate, net periodic benefit cost	4.25%	3.90%	4.80%
Expected return on plan assets	7.80%	7.80%	8.00%
CECONY
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	4.25%	4.25%	4.25%
Rate of compensation increase	4.25%	4.25%	4.35%
O&R
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	4.00%	4.00%	4.00%
Rate of compensation increase	4.00%	4.00%	4.25%

Pension Benefits - Schedule o80

Pension Benefits - Schedule of Expected Benefit Payments (Details) - Pension Benefits $ in Millions	Dec. 31, 2016USD ($)
Defined Benefit Plan Disclosure [Line Items]
2,017	$ 702
2,018	719
2,019	730
2,020	745
2,021	758
2022-2026	3,990
CECONY
Defined Benefit Plan Disclosure [Line Items]
2,017	653
2,018	670
2,019	679
2,020	693
2,021	705
2022-2026	$ 3,716

Pension Benefits - Schedule o81

Pension Benefits - Schedule of Plan Assets Allocations (Details) - Pension Benefits	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Plan Assets Percentage	100.00%	100.00%	100.00%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Range, Minimum	0.52%
Target Allocation Range, Maximum	0.64%
Plan Assets Percentage	58.00%	57.00%	58.00%
Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Range, Minimum	0.28%
Target Allocation Range, Maximum	0.38%
Plan Assets Percentage	33.00%	33.00%	32.00%
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Range, Minimum	7.00%
Target Allocation Range, Maximum	11.00%
Plan Assets Percentage	9.00%	10.00%	10.00%

Pension Benefits - Schedule o82

Pension Benefits - Schedule of Fair Value of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Private Equity
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets		$ 170
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets		1,248
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Funds for retiree health benefits	$ (270)	(282)
Funds for retiree health benefits measured at NAV per share (l)(n)	(37)	(43)
Total funds for retiree health benefits	(307)	325
Investments (excluding funds for retiree health benefits)	12,910	12,223
Pending activities	(438)	(464)
Total fair value of plan net assets	12,472	11,759	$ 11,495	$ 10,755
Pension Benefits | U.S. Equity
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	3,466	3,106
Pension Benefits | International Equity
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	3,558	3,220
Pension Benefits | U.S. Government Issued Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	1,337	2,222
Pension Benefits | Corporate Bonds Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	2,140	1,356
Pension Benefits | Structured Assets Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	1	1
Pension Benefits | Other Fixed Income Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	200	170
Pension Benefits | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	536	529
Pension Benefits | Futures
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	364	293
Pension Benefits | Total investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	11,602	10,897
Pension Benefits | Private Equity
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	247
Pension Benefits | Real Estate
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	1,139
Pension Benefits | Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	229	233
Pension Benefits | Investments Valued Using NAV Per Share
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	1,615	1,651
Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Funds for retiree health benefits	(165)	(162)
Investments (excluding funds for retiree health benefits)	6,931	6,094
Pension Benefits | Level 1 | U.S. Equity
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	3,466	3,106
Pension Benefits | Level 1 | International Equity
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	3,187	2,874
Pension Benefits | Level 1 | U.S. Government Issued Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	0	0
Pension Benefits | Level 1 | Corporate Bonds Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	0	0
Pension Benefits | Level 1 | Structured Assets Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	0	0
Pension Benefits | Level 1 | Other Fixed Income Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	0	0
Pension Benefits | Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	147	115
Pension Benefits | Level 1 | Futures
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	296	161
Pension Benefits | Level 1 | Total investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	7,096	6,256
Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Funds for retiree health benefits	(105)	(120)
Investments (excluding funds for retiree health benefits)	4,401	4,521
Pension Benefits | Level 2 | U.S. Equity
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	0
Pension Benefits | Level 2 | International Equity
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	371	346
Pension Benefits | Level 2 | U.S. Government Issued Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	1,337	2,222
Pension Benefits | Level 2 | Corporate Bonds Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	2,140	1,356
Pension Benefits | Level 2 | Structured Assets Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	1	1
Pension Benefits | Level 2 | Other Fixed Income Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	200	170
Pension Benefits | Level 2 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	389	414
Pension Benefits | Level 2 | Futures
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	68	132
Pension Benefits | Level 2 | Total investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	$ 4,506	$ 4,641

Pension Benefits - Schedule o83

Pension Benefits - Schedule of Employer Contribution to Defined Savings Plan (Details) - Pension Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Employer contribution to the defined savings plan	$ 36	$ 34	$ 32
CECONY
Defined Benefit Plan Disclosure [Line Items]
Employer contribution to the defined savings plan	$ 32	$ 29	$ 27

Other Postretirement Benefits -

Other Postretirement Benefits - Net Periodic Postretirement Benefit Costs (Details) - Other Postretirement Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 18	$ 20	$ 19
Interest cost on accumulated other postretirement benefit obligation	48	51	60
Expected return on plan assets	(77)	(78)	(77)
Recognition of net actuarial loss	5	31	57
Recognition of prior service cost	(20)	(20)	(19)
NET PERIODIC BENEFIT COST	(26)	4	40
Cost capitalized	11	(2)	(15)
Reconciliation to rate level	22	14	10
Cost charged to operating expenses	7	16	35
CECONY
Defined Benefit Plan Disclosure [Line Items]
Service cost	13	15	15
Interest cost on accumulated other postretirement benefit obligation	40	43	52
Expected return on plan assets	(67)	(68)	(68)
Recognition of net actuarial loss	3	28	51
Recognition of prior service cost	(14)	(14)	(15)
NET PERIODIC BENEFIT COST	(25)	4	35
Cost capitalized	10	(2)	(14)
Reconciliation to rate level	22	6	2
Cost charged to operating expenses	$ 7	$ 8	$ 23

Other Postretirement Benefits85

Other Postretirement Benefits - Schedule of Funded Status (Details) - Other Postretirement Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CHANGE IN BENEFIT OBLIGATION
Projected benefit obligation at beginning of year	$ 1,287	$ 1,411	$ 1,395
Service cost	18	20	19
Interest cost on accumulated other postretirement benefit obligation	48	51	60
Amendments	0	0	(12)
Net actuarial loss/(gain)	(57)	(103)	47
Benefits paid and administrative expenses	(134)	(127)	(134)
Participant contributions	36	35	36
PROJECTED BENEFIT OBLIGATION AT END OF YEAR	1,198	1,287	1,411
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	994	1,084	1,113
Actual return on plan assets	60	(6)	59
Employer contributions	7	6	7
EGWP payments	35	28	12
Participant contributions	36	35	36
Benefits paid	(157)	(153)	(143)
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	975	994	1,084
FUNDED STATUS	(223)	(293)	(327)
Unrecognized net loss/(gain)	(24)	28	78
Unrecognized prior service costs	(31)	(51)	(71)
CECONY
CHANGE IN BENEFIT OBLIGATION
Projected benefit obligation at beginning of year	1,093	1,203	1,198
Service cost	13	15	15
Interest cost on accumulated other postretirement benefit obligation	40	43	52
Amendments	0	0	0
Net actuarial loss/(gain)	(52)	(85)	28
Benefits paid and administrative expenses	(122)	(117)	(125)
Participant contributions	35	34	35
PROJECTED BENEFIT OBLIGATION AT END OF YEAR	1,007	1,093	1,203
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	870	950	977
Actual return on plan assets	52	(4)	54
Employer contributions	7	6	7
EGWP payments	33	26	11
Participant contributions	35	34	35
Benefits paid	(146)	(142)	(134)
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	851	870	950
FUNDED STATUS	(156)	(223)	(253)
Unrecognized net loss/(gain)	(42)	4	45
Unrecognized prior service costs	$ (18)	$ (32)	$ (46)

Other Postretirement Benefits86

Other Postretirement Benefits - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2014
CECONY | Clean Energy Business and RECO
Defined Benefit Plan Disclosure [Line Items]
Credit to OCI (net of taxes) for unrecognized net losses	$ 2
Debit to OCI (net of taxes) for unrecognized prior service costs	1
CECONY | Clean Energy Businesses
Defined Benefit Plan Disclosure [Line Items]
Credit to OCI (net of taxes) for unrecognized net losses	1
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Decrease in liability for other postretirement benefits	70
Increase in regulatory liabilities	32
Net losses unrecognized to be amortized	4
Prior service cost estimated to be amortized	$ (17)
Health care cost trend rate for net periodic benefit cost, current	6.00%
Health care cost trend rate for net periodic benefit cost	4.50%
Health care cost trend rate for benefit obligations, current	5.80%
Health care cost trend rate for benefit obligations	4.50%
Expected contributions	$ 14
Other Postretirement Benefits | Maximum
Defined Benefit Plan Disclosure [Line Items]
Increase in postretirement benefit obligations (less than)		$ 10
Other Postretirement Benefits | CECONY
Defined Benefit Plan Disclosure [Line Items]
Decrease in liability for other postretirement benefits	67
Increase in regulatory liabilities	32
Net losses unrecognized to be amortized	1
Prior service cost estimated to be amortized	(11)
Expected contributions	$ 10

Other Postretirement Benefits87

Other Postretirement Benefits - Schedule of Actuarial Assumptions (Details) - Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Expected Return on Plan Assets	7.00%	7.75%	7.75%
CECONY
Defined Benefit Plan Disclosure [Line Items]
Discount Rate, Benefit Obligations	4.00%	4.05%	3.75%
Discount Rate, Net Periodic Benefit Cost	4.05%	3.75%	4.50%
O&R
Defined Benefit Plan Disclosure [Line Items]
Discount Rate, Benefit Obligations	4.20%	4.20%	3.85%
Discount Rate, Net Periodic Benefit Cost	4.20%	3.85%	4.75%

Other Postretirement Benefits88

Other Postretirement Benefits - Schedule of Change of Assumed Health Care Cost Trend Rate (Details) - Other Postretirement Benefits $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Increase
Effect on accumulated other postretirement benefit obligation	$ (4)
Effect on service cost and interest cost components for 2016	1
Decrease
Effect on accumulated other postretirement benefit obligation	26
Effect on service cost and interest cost components for 2016	0
CECONY
Increase
Effect on accumulated other postretirement benefit obligation	(24)
Effect on service cost and interest cost components for 2016	(1)
Decrease
Effect on accumulated other postretirement benefit obligation	41
Effect on service cost and interest cost components for 2016	$ 1

Other Postretirement Benefits89

Other Postretirement Benefits - Schedule of Expected Benefit Payments (Details) - Other Postretirement Benefits $ in Millions	Dec. 31, 2016USD ($)
Defined Benefit Plan Disclosure [Line Items]
2,017	$ 86
2,018	85
2,019	83
2,020	80
2,021	78
2022-2026	375
CECONY
Defined Benefit Plan Disclosure [Line Items]
2,017	77
2,018	75
2,019	73
2,020	70
2,021	68
2022-2026	$ 322

Other Postretirement Benefits90

Other Postretirement Benefits - Schedule of Plan Assets Allocations (Details) - Other Postretirement Benefits - CECONY	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Plan Assets Percentage	100.00%	100.00%	100.00%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Range, Minimum	57.00%
Target Allocation Range, Maximum	73.00%
Plan Assets Percentage	60.00%	59.00%	59.00%
Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Range, Minimum	26.00%
Target Allocation Range, Maximum	44.00%
Plan Assets Percentage	40.00%	41.00%	41.00%

Other Postretirement Benefits91

Other Postretirement Benefits - Schedule of Fair Values of Plan Assets (Details) - Other Postretirement Benefits - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Funds for retiree health benefits	$ 270	$ 282
Investments (including funds for retiree health benefits)	924	942
Funds for retiree health benefits measured at NAV per share (l)(n)	37	43
Pending activities	14	9
Total fair value of plan net assets	975	994	$ 1,084	$ 1,113
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	391	393
Other Fixed Income Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	250	260
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	13	7
Total investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	654	660
Level 1
Defined Benefit Plan Disclosure [Line Items]
Funds for retiree health benefits	165	162
Investments (including funds for retiree health benefits)	165	162
Level 1 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	0	0
Level 1 | Other Fixed Income Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	0	0
Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	0	0
Level 1 | Total investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	0	0
Level 2
Defined Benefit Plan Disclosure [Line Items]
Funds for retiree health benefits	105	120
Investments (including funds for retiree health benefits)	759	780
Level 2 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	391	393
Level 2 | Other Fixed Income Debt
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	250	260
Level 2 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	13	7
Level 2 | Total investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan net assets	$ 654	$ 660

Environmental Matters - Accrued

Environmental Matters - Accrued Liabilities and Regulatory Assets (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Site Contingency [Line Items]
Accrued Liabilities	$ 753	$ 765
Regulatory assets	7,124	8,228
Manufactured gas plant sites
Site Contingency [Line Items]
Accrued Liabilities	664	679
Other Superfund Sites
Site Contingency [Line Items]
Accrued Liabilities	89	86
Superfund Sites
Site Contingency [Line Items]
Accrued Liabilities	753	765
Regulatory assets	823	904
CECONY
Site Contingency [Line Items]
Accrued Liabilities	655	665
Regulatory assets	6,563	7,603
CECONY | Manufactured gas plant sites
Site Contingency [Line Items]
Accrued Liabilities	567	579
CECONY | Other Superfund Sites
Site Contingency [Line Items]
Accrued Liabilities	88	86
CECONY | Superfund Sites
Site Contingency [Line Items]
Accrued Liabilities	655	665
Regulatory assets	$ 711	$ 800

Environmental Matters - Environ

Environmental Matters - Environmental Remediation Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Environmental Exit Cost [Line Items]
Remediation costs incurred	$ 34	$ 37
Insurance recoveries received	1	0
CECONY
Environmental Exit Cost [Line Items]
Remediation costs incurred	21	34
Insurance recoveries received	$ 1	$ 0

Environmental Matters - Additio

Environmental Matters - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Superfund Sites
Site Contingency [Line Items]
Remediation cost estimate	$ 55
Superfund Sites | Manufactured Gas Plant Sites | Maximum
Site Contingency [Line Items]
Estimated aggregate undiscounted potential liability related environmental contaminants (up to)	$ 2,800
CECONY | Asbestos Proceedings
Site Contingency [Line Items]
Estimated undiscounted asbestos liability (years)	15 years
CECONY | Superfund Sites
Site Contingency [Line Items]
Remediation cost estimate	$ 47
CECONY | Superfund Sites | Manufactured Gas Plant Sites | Maximum
Site Contingency [Line Items]
Estimated aggregate undiscounted potential liability related environmental contaminants (up to)	$ 2,600

Environmental Matters - Accru95

Environmental Matters - Accrued Liability for Asbestos Suits and Workers' Compensation Proceedings (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Site Contingency [Line Items]
Regulatory assets	$ 7,124	$ 8,228
Asbestos Suits
Site Contingency [Line Items]
Accrued liability	8	8
Regulatory assets	8	8
Workers' Compensation
Site Contingency [Line Items]
Accrued liability	88	86
Regulatory assets	13	11
CECONY
Site Contingency [Line Items]
Regulatory assets	6,563	7,603
CECONY | Asbestos Suits
Site Contingency [Line Items]
Accrued liability	7	7
Regulatory assets	7	7
CECONY | Workers' Compensation
Site Contingency [Line Items]
Accrued liability	83	81
Regulatory assets	$ 13	$ 11

Other Material Contingencies -

Other Material Contingencies - Additional Information (Details) $ in Millions	Mar. 12, 2014buildingpeople	Jul. 31, 2007lawsuitperson	Dec. 31, 2016USD ($)lawsuit	Dec. 31, 2015USD ($)	Dec. 31, 2014
Guarantor Obligations [Line Items]
Guarantee obligations maximum exposure			$ 2,370	$ 2,856
Payment Guarantee by CET Electric of Contributions to New York Transco LLC
Guarantor Obligations [Line Items]
Ownership interest, percentage					45.70%
Estimated project cost percentage			175.00%
Financial Guarantee in Behalf of CET Gas for Proposed Gas Transmission Project
Guarantor Obligations [Line Items]
Guarantee obligations maximum exposure			$ 25
Financial and Performance Guarantee for Commodity Transactions During Period in which Con Edison Solutions Provides Transition Services
Guarantor Obligations [Line Items]
Guarantee obligations maximum exposure			42
Financial Guarantee for Indemnity Agreements for Surety Bonds in Connection with Operation of Solar Energy Facilities and Energy Service Projects
Guarantor Obligations [Line Items]
Guarantee obligations maximum exposure			70
Certain Obligations Under Agreement to Sell the Retail Electric Supply Business
Guarantor Obligations [Line Items]
Guarantee obligations maximum exposure			53
Financial Guarantee to Public Utility Commission of Texas
Guarantor Obligations [Line Items]
Guarantee obligations maximum exposure			5
Manhattan Steam Main Rupture | CECONY
Guarantor Obligations [Line Items]
Number of person who died in stream rupture incident | person		1
Number of pending lawsuits | lawsuit		60
Estimated accrued liability for suits			25
Insurance receivable for suits			$ 25
Manhattan Explosion and Fire
Guarantor Obligations [Line Items]
Number of pending lawsuits | lawsuit			70
Number of buildings destroyed by fire | building	2
Number of people died in explosion and fire incident | people	8
Number of people injured in explosion and fire incident (more than) | people	50

Other Material Contingencies 97

Other Material Contingencies - Total Guarantees (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Guarantor Obligations [Line Items]
Total guarantees, by type and term	$ 2,370	$ 2,856
Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	1,048
Energy transactions
Guarantor Obligations [Line Items]
Total guarantees, by type and term	736
Renewable electric production projects
Guarantor Obligations [Line Items]
Total guarantees, by type and term	458
Other
Guarantor Obligations [Line Items]
Total guarantees, by type and term	128
0 – 3 years
Guarantor Obligations [Line Items]
Total guarantees, by type and term	1,605
0 – 3 years | Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	435
0 – 3 years | Energy transactions
Guarantor Obligations [Line Items]
Total guarantees, by type and term	603
0 – 3 years | Renewable electric production projects
Guarantor Obligations [Line Items]
Total guarantees, by type and term	439
0 – 3 years | Other
Guarantor Obligations [Line Items]
Total guarantees, by type and term	128
4 – 10 years
Guarantor Obligations [Line Items]
Total guarantees, by type and term	648
4 – 10 years | Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	613
4 – 10 years | Energy transactions
Guarantor Obligations [Line Items]
Total guarantees, by type and term	35
4 – 10 years | Renewable electric production projects
Guarantor Obligations [Line Items]
Total guarantees, by type and term	0
4 – 10 years | Other
Guarantor Obligations [Line Items]
Total guarantees, by type and term	0
Greater than 10 years
Guarantor Obligations [Line Items]
Total guarantees, by type and term	117
Greater than 10 years | Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	0
Greater than 10 years | Energy transactions
Guarantor Obligations [Line Items]
Total guarantees, by type and term	98
Greater than 10 years | Renewable electric production projects
Guarantor Obligations [Line Items]
Total guarantees, by type and term	19
Greater than 10 years | Other
Guarantor Obligations [Line Items]
Total guarantees, by type and term	$ 0

Electricity Purchase Agreemen98

Electricity Purchase Agreements - Summary of Significant Terms of Electricity Purchase Agreements (Details)	12 Months Ended
	Dec. 31, 2016MW
Brooklyn Navy Yard
Long-term Contract for Purchase of Electric Power [Line Items]
Plant Output (MW)	322
Contracted Output (MW)	293
Contract Term (Years)	40 years
Linden Cogeneration
Long-term Contract for Purchase of Electric Power [Line Items]
Plant Output (MW)	974
Contracted Output (MW)	630
Contract Term (Years)	25 years
Indian Point
Long-term Contract for Purchase of Electric Power [Line Items]
Plant Output (MW)	2,150
Contracted Output (MW)	500
Contract Term (Years)	16 years

Electricity Purchase Agreemen99

Electricity Purchase Agreements - Summary of Estimated Capacity and Other Fixed Payments (Details) $ in Millions	Dec. 31, 2016USD ($)
Long-term Contract for Purchase of Electric Power [Line Items]
2,017	$ 178
2,018	125
2,019	120
2,020	76
2,021	54
All Years Thereafter	710
CECONY
Long-term Contract for Purchase of Electric Power [Line Items]
2,017	178
2,018	125
2,019	119
2,020	75
2,021	54
All Years Thereafter	$ 710

Electricity Purchase Agreeme100

Electricity Purchase Agreements - Summary of Capacity, Energy and Other Fixed Payments (Details) - CECONY - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	$ 692	$ 865	$ 1,312
Linden Cogeneration
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	304	323	381
Indian Point
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	203	226	247
Astoria Energy
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	50	178	230
Astoria Generating Company
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	16	0	0
Brooklyn Navy Yard
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	119	113	133
Indeck Corinth
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	0	25	80
Selkirk
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	0	0	144
Independence
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	$ 0	$ 0	$ 97

Leases - Schedule of Capital Le

Leases - Schedule of Capital Leases (Details) - Common - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Property Subject to or Available for Operating Lease [Line Items]
Utility Plant	$ 3	$ 3
CECONY
Property Subject to or Available for Operating Lease [Line Items]
Utility Plant	$ 2	$ 2

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Operating Leased Assets [Line Items]
Accumulated amortization	$ 3	$ 3
CECONY
Operating Leased Assets [Line Items]
Accumulated amortization	$ 1	$ 2
Increase in annual payments, percentage	2.18%
Decrease in transformer installations, percentage	0.50%

Leases - Future Minimum Lease C

Leases - Future Minimum Lease Commitments (Details) $ in Millions	Dec. 31, 2016USD ($)
Capital Leased Assets [Line Items]
2,017	$ 1
2,018	1
2,019	0
2,020	0
2,021	0
All years thereafter	0
Total	2
Less: amount representing interest	0
Present value of net minimum lease payment	2
CECONY
Capital Leased Assets [Line Items]
2,017	1
2,018	1
2,019	0
2,020	0
2,021	0
All years thereafter	0
Total	2
Less: amount representing interest	0
Present value of net minimum lease payment	$ 2

Leases - Future Minimum Rental

Leases - Future Minimum Rental Payments for Operating Leases (Details) $ in Millions	Dec. 31, 2016USD ($)
Operating Leased Assets [Line Items]
2,017	$ 61
2,018	62
2,019	61
2,020	61
2,021	58
All years thereafter	788
Total	1,091
CECONY
Operating Leased Assets [Line Items]
2,017	53
2,018	54
2,019	54
2,020	54
2,021	53
All years thereafter	696
Total	$ 964

Goodwill and Other Intangibl105

Goodwill and Other Intangible Assets (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)business_acquisition	Dec. 31, 2015USD ($)business_acquisition
Goodwill [Line Items]
Goodwill	$ 428	$ 429
Impairment charge	15
Finite lived intangible assets, accumulated amortization	6	4
Amortization of Intangible Assets	2
Intangibles Future Amortization:
Year 1	8
Year 2	8
Year 3	8
Year 4	8
Year 5	8
Other Intangible Assets
Goodwill [Line Items]
Finite lived intangible assets, net	5	2
Finite lived intangible assets, accumulated amortization	5	4
O&R Merger
Goodwill [Line Items]
Goodwill	$ 406	406
Energy Service and Gas Storage Companies
Goodwill [Line Items]
Goodwill		$ 23
Number of businesses acquired included in goodwill impairment test | business_acquisition	2	2
Impairment charge	$ 15
Impairment charge, net of tax	12
Power Purchase
Goodwill [Line Items]
Finite lived intangible assets, net	119
Finite lived intangible assets, accumulated amortization	1
CECONY
Goodwill [Line Items]
Goodwill	245	$ 245
O&R
Goodwill [Line Items]
Goodwill	161	$ 161
Con Edison Solutions and Con Edison Development | Energy Service and Gas Storage Companies
Goodwill [Line Items]
Goodwill	$ 23
Con Edison Solutions | Energy Service and Gas Storage Companies
Goodwill [Line Items]
Number of businesses acquired included in goodwill impairment test | business_acquisition	2
Con Edison Solutions | Residential Solar Company
Goodwill [Line Items]
Goodwill	$ 14

Income Tax - Schedule of Compon

Income Tax - Schedule of Components of Income Tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
State
Current	$ (42)	$ 38	$ 59
Deferred	188	93	61
Federal
Current	(43)	(86)	(9)
Deferred	604	569	463
Amortization of investment tax credits	(9)	(9)	(6)
Total income tax expense	698	605	568
CECONY
State
Current	(1)	48	66
Deferred	114	82	65
Federal
Current	59	77	158
Deferred	435	372	271
Amortization of investment tax credits	(4)	(5)	(5)
Total income tax expense	$ 603	$ 574	$ 555

Income Tax - Schedule of Differ

Income Tax - Schedule of Differences on Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred tax liabilities:
Property basis differences	$ 9,446	$ 8,614
Regulatory assets:
Unrecognized pension and other postretirement costs	1,162	1,562
Future income tax	986	947
Environmental remediation costs	333	365
Deferred storm costs	23	75
Other regulatory assets	371	367
Equity investments	363	295
Total deferred tax liabilities	12,684	12,225
Deferred tax assets:
Accrued pension and other postretirement costs	581	982
Regulatory liabilities	822	836
Superfund and other environmental costs	304	308
Asset retirement obligations	99	97
Loss carryforwards	59	29
Tax credits carryforward	498	258
Valuation allowance	(16)	(15)
Other	303	362
Total deferred tax assets	2,650	2,857
Net deferred tax liabilities	10,034	9,368
Unamortized investment tax credits	171	169
Net deferred tax liabilities and unamortized investment tax credits	10,205	9,537
CECONY
Deferred tax liabilities:
Property basis differences	8,620	7,922
Regulatory assets:
Unrecognized pension and other postretirement costs	1,104	1,490
Future income tax	940	899
Environmental remediation costs	287	322
Deferred storm costs	1	45
Other regulatory assets	321	308
Equity investments	0	0
Total deferred tax liabilities	11,273	10,986
Deferred tax assets:
Accrued pension and other postretirement costs	467	857
Regulatory liabilities	728	752
Superfund and other environmental costs	265	268
Asset retirement obligations	92	94
Loss carryforwards	0	0
Tax credits carryforward	0	1
Valuation allowance	0	0
Other	312	292
Total deferred tax assets	1,864	2,264
Net deferred tax liabilities	9,409	8,722
Unamortized investment tax credits	41	33
Net deferred tax liabilities and unamortized investment tax credits	$ 9,450	$ 8,755

Income Tax - Schedule of Income

Income Tax - Schedule of Income Tax Reconciliation (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
STATUTORY TAX RATE
Federal	35.00%	35.00%	35.00%
Changes in computed taxes resulting from:
State income tax	4.00%	5.00%	5.00%
Cost of removal	(1.00%)	(5.00%)	(5.00%)
Renewable energy credits	(1.00%)	(1.00%)	(0.00%)
Research and development credits	(1.00%)	0.00%	0.00%
Other	0.00%	0.00%	(1.00%)
Effective tax rate	36.00%	34.00%	34.00%
CECONY
STATUTORY TAX RATE
Federal	35.00%	35.00%	35.00%
Changes in computed taxes resulting from:
State income tax	4.00%	5.00%	5.00%
Cost of removal	(1.00%)	(5.00%)	(5.00%)
Renewable energy credits	(0.00%)	(0.00%)	(0.00%)
Research and development credits	(1.00%)	0.00%	0.00%
Other	(1.00%)	0.00%	(1.00%)
Effective tax rate	36.00%	35.00%	34.00%

Income Tax - Additional Informa

Income Tax - Additional Information (Details)	1 Months Ended			12 Months Ended
	Feb. 29, 2016USD ($)	Jan. 31, 2016USD ($)	Jan. 31, 2015USD ($)	Dec. 31, 2016USD ($)claim	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, accelerated bonus depreciation				$ 32,000,000
Valuation allowance				207,000,000
Deferred tax asset, valuation allowance				16,000,000	$ 15,000,000
Deferred tax assets, charitable contribution carryforwards				$ 6,000,000	5,000,000
Corporate franchise tax rate				6.50%		7.10%
Decrease in accumulated deferred tax liabilities				$ 74,000,000
Decrease in regulatory asset				11,000,000
Increase in regulatory liability				62,000,000
Income tax refund requested		$ 160,000,000	$ 224,000,000
Income tax refund	$ 160,000,000
Decrease in uncertain tax positions resulting from settlement of claims filed in previous years				0	0	$ 0
Uncertain tax position from investment tax credit claim				19,000,000	1,000,000	27,000,000
Effective income tax rate reconciliation, uncertainty of taxes				35,000,000
Effective income tax rate reconciliation, uncertainty net of federal taxes				24,000,000
Change in effective tax rate upon completion of ongoing tax examinations				21,000,000
Change in effective tax rate upon completion of ongoing tax examinations, net of taxes				14,000,000
Unrecognized tax benefits that would have an impact on effective tax rate				24,000,000
Unrecognized tax benefits that would have an impact on effective tax rate, net of taxes				17,000,000
Penalties for uncertain tax positions				0	0	0
Amount of interest and penalties in their consolidated balance sheets				0	0
New York State
Operating Loss Carryforwards [Line Items]
Decrease in effective tax rate resulting from tax settlement				8,000,000
CECONY
Operating Loss Carryforwards [Line Items]
Deferred tax asset, valuation allowance				0	0
Decrease in accumulated deferred tax liabilities				69,000,000
Decrease in regulatory asset				10,000,000
Increase in regulatory liability				59,000,000
Income tax refund requested			$ 128,000,000
Income tax refund	$ 143,000,000
Decrease in uncertain tax positions resulting from settlement of claims filed in previous years				0	0	0
Uncertain tax position from investment tax credit claim				19,000,000	0	$ 2,000,000
Effective income tax rate reconciliation, uncertainty of taxes				17,000,000
Effective income tax rate reconciliation, uncertainty net of federal taxes				12,000,000
Change in effective tax rate upon completion of ongoing tax examinations				2,000,000
Unrecognized tax benefits that would have an impact on effective tax rate				3,000,000
CECONY | New York State
Operating Loss Carryforwards [Line Items]
Decrease in effective tax rate resulting from tax settlement				2,000,000
Charitable Contribution
Operating Loss Carryforwards [Line Items]
Deferred tax asset, valuation allowance					$ 3,000,000
General Business Tax Credit
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards				31,000,000
Renewable Energy Tax Credits
Operating Loss Carryforwards [Line Items]
Valuation allowance				498,000,000
Tax credit carryforward, valuation allowance				0
Charitable Contribution
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, valuation allowance				0
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards				204,000,000
Federal | Carryback to 2007 and 2014
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards				178,000,000
Federal | Year 2036
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards				26,000,000
New York City
Operating Loss Carryforwards [Line Items]
Deferred tax asset, valuation allowance				12,000,000
State
Operating Loss Carryforwards [Line Items]
Deferred tax asset, valuation allowance				$ 4,000,000
State | New York State
Operating Loss Carryforwards [Line Items]
Number of claims settled | claim				2
Decrease in uncertain tax positions resulting from settlement of claims filed in previous years				$ 11,000,000
Decrease in effective tax rate resulting from tax settlement, net of taxes				5,000,000
Uncertain tax position from investment tax credit claim				21,000,000
State | CECONY | New York State
Operating Loss Carryforwards [Line Items]
Decrease in effective tax rate resulting from tax settlement, net of taxes				$ 1,000,000

Income Tax - Summary of Unrecog

Income Tax - Summary of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 34	$ 34	$ 9
Additions based on tax positions related to the current year	2	0	0
Additions based on tax positions of prior years	19	1	27
Reductions for tax positions of prior years	(13)	0	(2)
Reductions from expiration of statute of limitations	0	(1)	0
Settlements	0	0	0
Balance at end of period	42	34	34
CECONY
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	2	2	0
Additions based on tax positions related to the current year	2	0	0
Additions based on tax positions of prior years	19	0	2
Reductions for tax positions of prior years	(2)	0	0
Reductions from expiration of statute of limitations	0	0	0
Settlements	0	0	0
Balance at end of period	$ 21	$ 2	$ 2

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit realized from stock options exercised	$ 20,000,000	$ 14,000,000	$ 12,000,000
Maximum employer contribution match (up to)	1
Amount employee contribution for employer match	9
Maximum employee investment per year (up to)	$ 25,000
Maximum percentage allowed to invest (not more than)	20.00%
CECONY
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit realized from stock options exercised	$ 18,000,000	12,000,000	10,000,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years
Income tax benefit realized from stock options exercised	$ 1,000,000	$ 1,000,000	$ 1,000,000
Stock Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award expiration period (years)	10 years
Performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock received upon vesting (shares)	1
Compensation expense to be recognized	$ 34,000,000
Nonvested awards, compensation cost not yet recognized, period for recognition (years)	1 year
Performance RSUs | CECONY
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense to be recognized	$ 27,000,000
Nonvested awards, compensation cost not yet recognized, period for recognition (years)	1 year
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years
Time-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense to be recognized	$ 2,000,000
Nonvested awards, compensation cost not yet recognized, period for recognition (years)	1 year
Weighted average grant date price per share (in dollars per share)	$ 76.62
Time-based Awards | CECONY
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense to be recognized	$ 2,000,000
Nonvested awards, compensation cost not yet recognized, period for recognition (years)	1 year
Weighted average grant date price per share (in dollars per share)	$ 76.62
2013 LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock that can be awarded under the plan	5,000,000
TSR Portion | Performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Adjustment percentage used for Performance awards	50.00%
Factor used for adjustment of Performance awards, low end (percent)	0.00%
Factor used for adjustment of Performance awards, high end (percent)	200.00%
Weighted average grant date price per share (in dollars per share)	$ 83.16
TSR Portion | Performance RSUs | CECONY
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date price per share (in dollars per share)	$ 82.73
Non-TSR Portion | Performance RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Adjustment percentage used for Performance awards	50.00%
Factor used for adjustment of Performance awards, low end (percent)	0.00%
Factor used for adjustment of Performance awards, high end (percent)	200.00%
Weighted average grant date price per share (in dollars per share)	$ 72.10
Non-TSR Portion | Performance RSUs | CECONY
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date price per share (in dollars per share)	$ 72.34
LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units issued	27,600
Weighted average grant date price per share (in dollars per share)	$ 74.37
Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares purchased on the open market	720,268	761,784	708,276
Weighted average share price per share, on shares purchased on open market	$ 72.67	$ 62.75	$ 56.23

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 50	$ 34	$ 29
Income tax benefit	20	14	12
Performance-based restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	42	27	22
Time-based restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2	1	2
Non-employee director deferred stock compensation
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2	2	2
Stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	4	4	3
CECONY
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	44	29	26
Income tax benefit	18	12	10
CECONY | Performance-based restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	36	23	19
CECONY | Time-based restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2	1	2
CECONY | Non-employee director deferred stock compensation
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2	2	2
CECONY | Stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4	$ 3	$ 3

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Status of Stock Options (Details)	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Shares
Outstanding at beginning of period (in shares) | shares	79,125
Exercised (in shares) | shares	79,125
Forfeited (in shares) | shares	0
Outstanding at end of period (in shares) | shares	0
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 43.50
Exercised (in dollars per share) | $ / shares	43.50
Forfeited (in dollars per share) | $ / shares	0
Outstanding at end of period (in dollars per share) | $ / shares	$ 0
CECONY
Shares
Outstanding at beginning of period (in shares) | shares	65,775
Exercised (in shares) | shares	65,775
Forfeited (in shares) | shares	0
Outstanding at end of period (in shares) | shares	0
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 43.50
Exercised (in dollars per share) | $ / shares	43.50
Forfeited (in dollars per share) | $ / shares	0
Outstanding at end of period (in dollars per share) | $ / shares	$ 0

Stock-Based Compensation - S114

Stock-Based Compensation - Summary of Stock Options (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Aggregate intrinsic value
Options outstanding	$ 0	$ 2
Options exercised	2	3
Cash received by Con Edison for payment of exercise price	3	6
CECONY
Aggregate intrinsic value
Options outstanding	0	1
Options exercised	2	3
Cash received by Con Edison for payment of exercise price	$ 3	$ 5

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Used to Calculate Fair Value (Details) - Performance RSUs	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	0.85%	0.64%	0.23%
Risk-free interest rate, maximum	1.20%	3.28%	3.07%
Expected term (years)	3 years	3 years	3 years
Expected share price volatility, minimum (percent)	17.72%
Expected share price volatility, maximum (percent)	18.22%
Expected share price volatility (percent)		15.82%	13.14%

Stock-Based Compensation - S116

Stock-Based Compensation - Summary of Changes in Status of Performance RSUs' (Details) - Performance RSUs	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Units
Non-vested at beginning of period (in units) | shares	1,078,339
Granted (in units) | shares	386,400
Vested (in units) | shares	(351,230)
Forfeited (in units) | shares	(26,372)
Non-vested at end of period (in units) | shares	1,087,137
CECONY
Units
Non-vested at beginning of period (in units) | shares	853,257
Granted (in units) | shares	295,300
Vested (in units) | shares	(285,162)
Forfeited (in units) | shares	(15,053)
Non-vested at end of period (in units) | shares	848,342
TSR Portion
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share)	$ 45.26
Granted (in dollars per share)	83.16
Vested (in dollars per share)	55.16
Forfeited (in dollars per share)	48.48
Non-vested at end of period (in dollars per share)	$ 55.45
Adjustment percentage used for Performance awards	50.00%
TSR Portion | CECONY
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share)	$ 45.37
Granted (in dollars per share)	82.73
Vested (in dollars per share)	55.21
Forfeited (in dollars per share)	53.61
Non-vested at end of period (in dollars per share)	54.92
Non-TSR Portion
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share)	58.08
Granted (in dollars per share)	72.10
Vested (in dollars per share)	57.96
Forfeited (in dollars per share)	61.03
Non-vested at end of period (in dollars per share)	$ 63.03
Adjustment percentage used for Performance awards	50.00%
Non-TSR Portion | CECONY
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share)	$ 58.12
Granted (in dollars per share)	72.34
Vested (in dollars per share)	58.07
Forfeited (in dollars per share)	63.05
Non-vested at end of period (in dollars per share)	$ 63

Stock-Based Compensation - S117

Stock-Based Compensation - Summary of Changes in Status of Time-Based Awards (Details) - Time-based Awards	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Units
Non-vested at beginning of period (in units) | shares	64,980
Granted (in units) | shares	23,000
Vested (in units) | shares	(20,900)
Forfeited (in units) | shares	(1,100)
Non-vested at end of period (in units) | shares	65,980
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share) | $ / shares	$ 58.56
Granted (in dollars per share) | $ / shares	76.62
Vested (in dollars per share) | $ / shares	61.03
Forfeited (in dollars per share) | $ / shares	60.13
Non-vested at end of period (in dollars per share) | $ / shares	$ 64.04
CECONY
Units
Non-vested at beginning of period (in units) | shares	61,630
Granted (in units) | shares	21,800
Vested (in units) | shares	(19,800)
Forfeited (in units) | shares	(1,050)
Non-vested at end of period (in units) | shares	62,580
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share) | $ / shares	$ 58.55
Granted (in dollars per share) | $ / shares	76.62
Vested (in dollars per share) | $ / shares	61.03
Forfeited (in dollars per share) | $ / shares	60.43
Non-vested at end of period (in dollars per share) | $ / shares	$ 64.03

Financial Information by Bus118

Financial Information by Business Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 12,075	$ 12,554	$ 12,919
Depreciation and amortization	1,216	1,130	1,071
Operating income	2,575	2,427	2,209
Other Income (deductions)	64	24	42
Interest charges	696	653	591
Income taxes on operating income	714	644	589
Total assets	48,255	45,642	44,071
Capital expenditures	5,235	3,418	2,721
Income taxes on non-operating income	16	40	21
New Accounting Pronouncement, Early Adoption, Effect
Segment Reporting Information [Line Items]
Total assets			237
CECONY
Segment Reporting Information [Line Items]
Revenues	10,165	10,328	10,786
Depreciation and amortization	1,106	1,040	991
Operating income	2,262	2,247	2,139
Other Income (deductions)	0	(5)	11
Interest charges	603	584	537
Total assets	40,856	40,230
Income taxes on non-operating income	14	14	7
Operating segment | Clean Energy Businesses
Segment Reporting Information [Line Items]
Revenues	1,091	1,383	1,244
Depreciation and amortization	42	22	19
Operating income	183	58	(60)
Other Income (deductions)	21	35	28
Interest charges	34	11	(8)
Income taxes on operating income	53	22	(8)
Total assets	2,551	1,680	1,013
Capital expenditures	1,235	823	447
Operating segment | Con Edison Transmission
Segment Reporting Information [Line Items]
Revenues	0	0	0
Depreciation and amortization	0	0	0
Operating income	(3)	0	0
Other Income (deductions)	43	0	0
Interest charges	6	0	0
Income taxes on operating income	0	0	0
Total assets	1,150	3	1
Capital expenditures	1,078	0	0
Operating segment | CECONY
Segment Reporting Information [Line Items]
Revenues	10,165	10,328	10,786
Depreciation and amortization	1,106	1,040	991
Operating income	2,262	2,247	2,139
Other Income (deductions)	0	(5)	11
Interest charges	603	584	537
Income taxes on operating income	617	588	562
Total assets	40,856	40,230	39,443
Capital expenditures	2,756	2,435	2,132
Operating segment | CECONY | Electric
Segment Reporting Information [Line Items]
Revenues	8,106	8,172	8,437
Depreciation and amortization	865	820	781
Operating income	1,847	1,798	1,712
Other Income (deductions)	2	(2)	8
Interest charges	459	447	412
Income taxes on operating income	495	447	425
Total assets	30,708	30,603	30,295
Capital expenditures	1,819	1,658	1,500
Operating segment | CECONY | Gas
Segment Reporting Information [Line Items]
Revenues	1,508	1,527	1,721
Depreciation and amortization	159	142	132
Operating income	357	356	314
Other Income (deductions)	(1)	(2)	2
Interest charges	105	96	89
Income taxes on operating income	92	100	88
Total assets	7,553	6,974	6,478
Capital expenditures	811	671	549
Operating segment | CECONY | Steam
Segment Reporting Information [Line Items]
Revenues	551	629	628
Depreciation and amortization	82	78	78
Operating income	58	93	113
Other Income (deductions)	(1)	(1)	1
Interest charges	39	41	36
Income taxes on operating income	30	41	49
Total assets	2,595	2,653	2,670
Capital expenditures	126	106	83
Operating segment | O&R
Segment Reporting Information [Line Items]
Revenues	821	845	892
Depreciation and amortization	67	68	61
Operating income	130	121	128
Other Income (deductions)	1	(4)	3
Interest charges	36	35	35
Income taxes on operating income	40	33	35
Total assets	2,758	2,719	2,810
Capital expenditures	166	160	142
Operating segment | O&R | Electric
Segment Reporting Information [Line Items]
Revenues	637	663	680
Depreciation and amortization	49	50	46
Operating income	95	103	103
Other Income (deductions)	1	(2)	3
Interest charges	24	23	24
Income taxes on operating income	30	31	29
Total assets	1,949	2,140	2,023
Capital expenditures	114	114	105
Operating segment | O&R | Gas
Segment Reporting Information [Line Items]
Revenues	184	182	212
Depreciation and amortization	18	18	15
Operating income	35	18	25
Other Income (deductions)	0	(2)	0
Interest charges	12	12	10
Income taxes on operating income	10	2	6
Total assets	809	579	786
Capital expenditures	52	46	37
Other
Segment Reporting Information [Line Items]
Revenues	(2)	(2)	(3)
Depreciation and amortization	1	0	0
Operating income	3	1	2
Other Income (deductions)	(1)	(2)	0
Interest charges	17	23	27
Income taxes on operating income	4	1	0
Total assets	940	1,010	804
Capital expenditures	0	0
Other | O&R
Segment Reporting Information [Line Items]
Revenues	0	0	0
Depreciation and amortization	0	0	0
Operating income	0	0	0
Other Income (deductions)	0	0	0
Interest charges	0	0	1
Income taxes on operating income	0	0	0
Total assets	0	0	1
Capital expenditures	0	0	0
Inter-segment
Segment Reporting Information [Line Items]
Revenues	(7)	2	10
Inter-segment | Clean Energy Businesses
Segment Reporting Information [Line Items]
Revenues	7	(2)	(10)
Inter-segment | CECONY
Segment Reporting Information [Line Items]
Revenues	(111)	(110)	(106)
Inter-segment | CECONY | Electric
Segment Reporting Information [Line Items]
Revenues	17	18	16
Inter-segment | CECONY | Gas
Segment Reporting Information [Line Items]
Revenues	6	6	6
Inter-segment | CECONY | Steam
Segment Reporting Information [Line Items]
Revenues	$ 88	$ 86	$ 84

Derivative Instruments and H119

Derivative Instruments and Hedging Activities - Fair Values of Commodity Derivatives Including Offsetting of Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair value of derivative assets
Net Amounts of Assets/ (Liabilities)	$ 363	$ 345
Fair value of derivative liabilities
Net Amounts of Assets/ (Liabilities)	(117)	(183)
Net fair value derivative assets/(liabilities)
Gross Amounts of Recognized Assets/ (Liabilities)	(99)	(207)
Gross Amounts Offset	6	46
Net Amounts of Assets/ (Liabilities)	(93)	(161)
Margin deposits	7	26
Interest Rate Swap
Fair value of derivative liabilities
Net Amounts of Assets/ (Liabilities)	(1)	0
CECONY
Fair value of derivative assets
Net Amounts of Assets/ (Liabilities)	326	311
Net fair value derivative assets/(liabilities)
Gross Amounts of Recognized Assets/ (Liabilities)	(95)	(125)
Gross Amounts Offset	9	48
Net Amounts of Assets/ (Liabilities)	(86)	(77)
Margin deposits	7	26
Fair Value of Derivative Liabilities, Current
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(138)	(144)
Gross Amounts Offset	61	78
Net Amounts of Assets/ (Liabilities)	(77)	(66)
Fair Value of Derivative Liabilities, Current | CECONY
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(111)	(121)
Gross Amounts Offset	45	71
Net Amounts of Assets/ (Liabilities)	(66)	(50)
Fair Value of Derivative Liabilities, Liabilities Held For Sale, Current
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	0	(115)
Gross Amounts Offset	0	50
Net Amounts of Assets/ (Liabilities)	0	(65)
Fair Value of Derivative Liabilities, Non-current
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(91)	(102)
Gross Amounts Offset	52	63
Net Amounts of Assets/ (Liabilities)	(39)	(39)
Fair Value of Derivative Liabilities, Non-current | CECONY
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(77)	(92)
Gross Amounts Offset	44	56
Net Amounts of Assets/ (Liabilities)	(33)	(36)
Fair Value of Derivative Liabilities, Liabilities Held For Sale, Noncurrent
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	0	(28)
Gross Amounts Offset	0	15
Net Amounts of Assets/ (Liabilities)	0	(13)
Fair Value of Derivative Liabilities
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(229)	(389)
Gross Amounts Offset	113	206
Net Amounts of Assets/ (Liabilities)	(116)	(183)
Fair Value of Derivative Liabilities | CECONY
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(188)	(213)
Gross Amounts Offset	89	127
Net Amounts of Assets/ (Liabilities)	(99)	(86)
Fair Value of Derivative Assets, Current
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	81	59
Gross Amounts Offset	(64)	(41)
Net Amounts of Assets/ (Liabilities)	17	18
Fair Value of Derivative Assets, Current | CECONY
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	52	40
Gross Amounts Offset	(45)	(32)
Net Amounts of Assets/ (Liabilities)	7	8
Fair Value of Derivative Assets, Assets Held for Sale, Current
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	0	51
Gross Amounts Offset	0	(50)
Net Amounts of Assets/ (Liabilities)	0	1
Fair Value of Derivative Assets, Non-current
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	49	57
Gross Amounts Offset	(43)	(54)
Net Amounts of Assets/ (Liabilities)	6	3
Fair Value of Derivative Assets, Non-current | CECONY
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	41	48
Gross Amounts Offset	(35)	(47)
Net Amounts of Assets/ (Liabilities)	6	1
Fair Value of Derivative Assets, Assets Held for Sale, Noncurrent
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	0	15
Gross Amounts Offset	0	(15)
Net Amounts of Assets/ (Liabilities)	0	0
Fair Value of Derivative Assets
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	130	182
Gross Amounts Offset	(107)	(160)
Net Amounts of Assets/ (Liabilities)	23	22
Fair Value of Derivative Assets | CECONY
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	93	88
Gross Amounts Offset	(80)	(79)
Net Amounts of Assets/ (Liabilities)	$ 13	$ 9

Derivative Instruments and H120

Derivative Instruments and Hedging Activities - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Investment Holdings [Line Items]
Energy supply and hedging activities credit exposure total	$ 62
Makeup of net credit exposure with commodity exchange brokers	25
Makeup of net credit exposure with investment-grade counterparties	17
Makeup of net credit exposure independent system operators	9
Makeup of net credit exposure non-investment grade/non-rated counterparties	11
Derivative liabilities	117	$ 183
Interest Rate Swap
Investment Holdings [Line Items]
Derivative liabilities	1	$ 0
CECONY
Investment Holdings [Line Items]
Energy supply and hedging activities credit exposure total	20
Makeup of net credit exposure with commodity exchange brokers	14
Makeup of net credit exposure with investment-grade counterparties	$ 6
Clean Energy Businesses | Coram | Interest Rate Swap
Investment Holdings [Line Items]
Derivative, fixed interest rate	2.0855%
Derivative liabilities	$ 1

Derivative Instruments and H121

Derivative Instruments and Hedging Activities - Realized and Unrealized Gains or Losses on Commodity Derivatives (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	$ 24	$ 2
Total deferred gains/(losses)	(188)	(177)
Net deferred gains/(losses)	(164)	(175)
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	(203)	(186)
Purchased power expense
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	(101)	(109)
Unrealized gain/(loss) on derivatives	11	(1)
Gas purchased for resale
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	(112)	(106)
Non-utility revenue
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	9	30
Other operations and maintenance expense
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	1	(1)
Unrealized gain/(loss) on derivatives	1	(1)
Non-utility operating revenue
Pre-tax gain/(loss) recognized in income
Unrealized gain/(loss) on derivatives	(5)	1
Deferred Derivative Gains,Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	23	1
Deferred Derivative Gains, Noncurrent
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	1	1
Deferred Derivative Losses, Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	22	(16)
Recoverable Energy Costs, Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	(212)	(136)
Deferred Derivative Losses, Noncurrent
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	2	(25)
CECONY
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	20	2
Total deferred gains/(losses)	(172)	(161)
Net deferred gains/(losses)	(152)	(159)
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	1	(1)
CECONY | Purchased power expense
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	0	0
CECONY | Gas purchased for resale
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	0	0
CECONY | Non-utility revenue
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	0	0
CECONY | Other operations and maintenance expense
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	1	(1)
Unrealized gain/(loss) on derivatives	1	(1)
CECONY | Deferred Derivative Gains,Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	18	2
CECONY | Deferred Derivative Gains, Noncurrent
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	2	0
CECONY | Deferred Derivative Losses, Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	18	(11)
CECONY | Recoverable Energy Costs, Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	(194)	(127)
CECONY | Deferred Derivative Losses, Noncurrent
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	$ 4	$ (23)

Derivative Instruments and H122

Derivative Instruments and Hedging Activities - Hedged Volume of Derivative Transactions (Details) gal in Thousands	Dec. 31, 2016MWMMBTUgalMWh
Electric Energy
Derivatives, Fair Value [Line Items]
Notional amount | MWh	21,235,830
Capacity
Derivatives, Fair Value [Line Items]
Notional amount | MW	13,616
Natural Gas
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	77,248,786
Refined Fuels
Derivatives, Fair Value [Line Items]
Notional amount | gal	3,696
CECONY | Electric Energy
Derivatives, Fair Value [Line Items]
Notional amount | MWh	19,258,400
CECONY | Capacity
Derivatives, Fair Value [Line Items]
Notional amount | MW	7,500
CECONY | Natural Gas
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	71,060,000
CECONY | Refined Fuels
Derivatives, Fair Value [Line Items]
Notional amount | gal	3,696

Derivative Instruments and H123

Derivative Instruments and Hedging Activities - Aggregate Fair Value of Companies' Derivative Instruments with Credit-Risk-Related Contingent Features (Details) $ in Millions	Dec. 31, 2016USD ($)
Derivatives, Fair Value [Line Items]
Aggregate fair value – net liabilities	$ 113
Collateral posted	43
Downgrade One Level from Current Ratings
Derivatives, Fair Value [Line Items]
Additional collateral	11
Downgrade to Below Investment Grade from Current Ratings
Derivatives, Fair Value [Line Items]
Additional collateral	75
Derivatives in net asset position additional collateral	15
Additional Collateral Required Due To Loss Of Unsecured Credit
Derivatives, Fair Value [Line Items]
Collateral posted	43
CECONY
Derivatives, Fair Value [Line Items]
Aggregate fair value – net liabilities	103
Collateral posted	42
CECONY | Downgrade One Level from Current Ratings
Derivatives, Fair Value [Line Items]
Additional collateral	10
CECONY | Downgrade to Below Investment Grade from Current Ratings
Derivatives, Fair Value [Line Items]
Additional collateral	$ 65

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 363	$ 345
Derivative liabilities	117	183
CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	326	311
Netting Adjustment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	(24)	(56)
Derivative liabilities	(38)	(128)
Netting Adjustment | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	(10)	17
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	236	187
Derivative liabilities	4	17
Level 1 | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	210	172
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	144	200
Derivative liabilities	145	286
Level 2 | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	125	114
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	7	14
Derivative liabilities	6	8
Level 3 | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1	8
Commodity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	30	47
Derivative liabilities	116	105
Commodity | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	20	35
Derivative liabilities	99	86
Commodity | Netting Adjustment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	(24)	7
Derivative liabilities	(38)	(65)
Commodity | Netting Adjustment | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	(10)	17
Derivative liabilities	(26)	(57)
Commodity | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	14	2
Derivative liabilities	4	16
Commodity | Level 1 | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	10	1
Derivative liabilities	1	14
Commodity | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	33	25
Derivative liabilities	144	153
Commodity | Level 2 | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	19	9
Derivative liabilities	124	129
Commodity | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	7	13
Derivative liabilities	6	1
Commodity | Level 3 | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1	8
Derivative liabilities	0	0
Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	1	0
Interest Rate Swap | Netting Adjustment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Interest Rate Swap | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Interest Rate Swap | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	1	0
Interest Rate Swap | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Commodity Held For Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	1
Derivative liabilities	0	78
Commodity Held For Sale | Netting Adjustment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	(63)
Derivative liabilities	0	(63)
Commodity Held For Sale | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	1
Commodity Held For Sale | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	63
Derivative liabilities	0	133
Commodity Held For Sale | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	1
Derivative liabilities	0	7
Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	333	297
Other | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	306	276
Other | Netting Adjustment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Other | Netting Adjustment | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Other | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	222	185
Other | Level 1 | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	200	171
Other | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	111	112
Other | Level 2 | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	106	105
Other | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Other | Level 3 | CECONY
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 0	$ 0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Commodity Derivatives (Details) - Level 3 $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)$ / MWh$ / kW-month
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives | $	$ 1
Electricity
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives | $	$ (1)
Electricity | Forward Energy Prices | Minimum
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per MWh/Dt) | $ / MWh	37.75
Electricity | Forward Energy Prices | Maximum
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per MWh/Dt) | $ / MWh	55
Electricity | Forward Capacity Prices | Minimum
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per MWh/Dt) | $ / kW-month	2.42
Electricity | Forward Capacity Prices | Maximum
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per MWh/Dt) | $ / kW-month	10.25
Transmission Congestion Contracts/Financial Transmission Rights
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives | $	$ 2
Transmission Congestion Contracts/Financial Transmission Rights | Discount for Inter Zonal Forward Price Curves
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (percent)	50.00%
Transmission Congestion Contracts/Financial Transmission Rights | Discount for Historical Monthly Realized Settlements | Minimum
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (percent)	(75.20%)
Transmission Congestion Contracts/Financial Transmission Rights | Discount for Historical Monthly Realized Settlements | Maximum
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (percent)	58.90%
Transmission Congestion Contracts/Financial Transmission Rights | Inter Zonal Forward Price Curves Adjusted for Historical Zonal Losses | Minimum
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per kW-month) | $ / MWh	1.11
Transmission Congestion Contracts/Financial Transmission Rights | Inter Zonal Forward Price Curves Adjusted for Historical Zonal Losses | Maximum
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per kW-month) | $ / MWh	2.90
Transmission Congestion Contracts | CECONY
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives | $	$ 1
Transmission Congestion Contracts | Discount for Inter Zonal Forward Price Curves | CECONY
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (percent)	50.00%
Transmission Congestion Contracts | Discount for Historical Monthly Realized Settlements | Minimum | CECONY
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (percent)	(75.20%)
Transmission Congestion Contracts | Discount for Historical Monthly Realized Settlements | Maximum | CECONY
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (percent)	58.90%

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - Purchased power expense - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, assets measured on recurring basis, change in unrealized loss	$ 1	$ 8
Clean Energy Businesses
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loss on Level 3 energy derivative liabilities	$ 6	$ 14

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation of Beginning and Ending Net Balances for Assets and Liabilities Measured at Level 3 Fair Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 6	$ 20
Included in earnings	(7)	(20)
Included in regulatory assets and liabilities	(6)	1
Purchases	4	11
Sales	4	0
Settlements	0	(6)
Ending Balance	1	6
CECONY
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	8	13
Included in earnings	(1)	(6)
Included in regulatory assets and liabilities	(6)	0
Purchases	2	5
Sales	0	0
Settlements	(2)	(4)
Ending Balance	$ 1	$ 8

Variable Interest Entities - Ad

Variable Interest Entities - Additional Information (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2016USD ($)VIE	Dec. 31, 2015USD ($)MW
Variable Interest Entity [Line Items]
Noncontrolling interest		$ 8	$ 9
Variable Interest Entity, Primary Beneficiary | Texas Solar 4
Variable Interest Entity [Line Items]
Percentage of variable interests	80.00%	80.00%
VIE consolidated, carrying amount, assets and liabilities, net		$ 54	58
Noncontrolling Interest
Variable Interest Entity [Line Items]
Noncontrolling interest		$ 7	$ 9
Texas | Variable Interest Entity, Primary Beneficiary | Texas Solar 4
Variable Interest Entity [Line Items]
Generating capacity (MW AC) | MW			40
CECONY
Variable Interest Entity [Line Items]
Number of potential VIEs, long-term electricity purchase agreements | VIE		2

Variable Interest Entities - Ne

Variable Interest Entities - Net Assets of Texas Solar 4 (Details) - Texas Solar 4 - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Restricted cash	$ 8	$ 9
Receivable from parent company	35	32
Non-utility property, less accumulated depreciation of $9 and $5, respectively	104	107
Other assets	8	11
Total assets	155	159
Long-term debt due within one year	3	2
Other liabilities	38	37
Long-term debt	60	62
Total liabilities	101	101
Accumulated depreciation	$ 9	$ 5

Variable Interest Entities - Su

Variable Interest Entities - Summary of VIEs (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2016USD ($)MW
Variable Interest Entity, Not Primary Beneficiary | Copper Mountain Solar 3 | Nevada
Variable Interest Entity [Line Items]
Generating Capacity Owned (MW AC) | MW		128
Power Purchase Agreement Term in Years		20 years
Maximum Exposure to Loss		$ 179,000,000
Variable Interest Entity, Not Primary Beneficiary | Mesquite Solar 1 | Arizona
Variable Interest Entity [Line Items]
Generating Capacity Owned (MW AC) | MW		83
Power Purchase Agreement Term in Years		20 years
Maximum Exposure to Loss		$ 108,000,000
Variable Interest Entity, Not Primary Beneficiary | Copper Mountain Solar 2 | Nevada
Variable Interest Entity [Line Items]
Generating Capacity Owned (MW AC) | MW		75
Power Purchase Agreement Term in Years		25 years
Maximum Exposure to Loss		$ 84,000,000
Variable Interest Entity, Not Primary Beneficiary | California Solar | California
Variable Interest Entity [Line Items]
Generating Capacity Owned (MW AC) | MW		55
Power Purchase Agreement Term in Years		25 years
Maximum Exposure to Loss		$ 69,000,000
Variable Interest Entity, Not Primary Beneficiary | Broken Bow II | Nebraska
Variable Interest Entity [Line Items]
Generating Capacity Owned (MW AC) | MW		38
Power Purchase Agreement Term in Years		25 years
Maximum Exposure to Loss		$ 48,000,000
Variable Interest Entity, Primary Beneficiary | Texas Solar 4
Variable Interest Entity [Line Items]
Percentage of variable interests	80.00%	80.00%
Maximum exposure for consolidated investments		$ 7,000,000
Variable Interest Entity, Primary Beneficiary | Texas Solar 4 | Texas
Variable Interest Entity [Line Items]
Generating Capacity Owned (MW AC) | MW		32
Power Purchase Agreement Term in Years		25 years
Maximum Exposure to Loss		$ 47,000,000
Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure
Variable Interest Entity [Line Items]
Percentage of variable interests		50.00%

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Regulatory Liabilities [Line Items]
Accrued liability - asset retirement obligations	$ 246	$ 242
Increase in liabilities for asset retirement obligations due to changes in estimated cash flows	29
Asset retirement obligations, accretion expense	10
Asset retirement obligations, liabilities settled	35
Asset retirement obligations, reductions	37	23
CECONY
Regulatory Liabilities [Line Items]
Accrued liability - asset retirement obligations	227	234
Increase in liabilities for asset retirement obligations due to changes in estimated cash flows	19
Asset retirement obligations, accretion expense	9
Asset retirement obligations, liabilities settled	35
Asset retirement obligations, reductions	$ 37	$ 23

Related Party Transactions - Su

Related Party Transactions - Summary of Costs of Administrative and Other Services Provided and Received (Details) - CECONY - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Cost of services provided	$ 108	$ 99	$ 90
Cost of services received	$ 64	$ 60	$ 57

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details)	7 Months Ended	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2016USD ($)agreement	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Jan. 31, 2016
Related Party Transaction [Line Items]
Gas purchased for resale		$ 477,000,000	$ 495,000,000	$ 811,000,000
CECONY
Related Party Transaction [Line Items]
Sale of natural gas		47,000,000	54,000,000	80,000,000
Gas purchased for resale		319,000,000	337,000,000	$ 609,000,000
Funding limit of CECONY to O&R (not to exceed)		$ 250,000,000
CECONY | Related Party, Lending of Funds
Related Party Transaction [Line Items]
Lending period (not more than) (months)		12 months
CECONY | Equity Method Investee | Stagecoach | Purchased Power Costs
Related Party Transaction [Line Items]
Gas purchased for resale	$ 18,000,000
CECONY | Equity Method Investee | Stagecoach | Purchased Power Costs | Clean Energy Businesses
Related Party Transaction [Line Items]
Number of electricity sales agreements entered into | agreement		2
CET Electric
Related Party Transaction [Line Items]
Ownership interest, percentage	45.70%	45.70%			45.70%
O&R
Related Party Transaction [Line Items]
Outstanding loans to O&R		$ 0	$ 0

Acquisitions, Investments an134

Acquisitions, Investments and Dispositions - Texas Solar 7 (Details) - Texas Solar 7 - Texas $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2016USD ($)MW	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Percentage of voting interest acquired	100.00%
Generating capacity (MW AC) | MW	106
Payments to acquire business	$ 227
Non-utility construction work in progress	218
Receivable from parent company	$ 9
Net assets		$ 127
Intangible assets		$ 41

Acquisitions, Investments an135

Acquisitions, Investments and Dispositions - Mountain Valley Pipeline (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2016	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Equity method investment			$ 488	$ 574
Mountain Valley Pipeline
Schedule of Equity Method Investments [Line Items]
Percentage of equity interest acquired	12.50%
Payments to acquire equity interest	$ 18
Equity method investment			$ 48
Mountain Valley Pipeline | Gas | Minimum | Scenario, Forecast
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity interest		$ 3,000
Mountain Valley Pipeline | Gas | Maximum | Scenario, Forecast
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity interest		$ 3,500

Acquisitions, Investments an136

Acquisitions, Investments and Dispositions - NY Transco (Details) - USD ($) $ in Millions	1 Months Ended
	May 31, 2016	Dec. 31, 2016	Jan. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Equity method investment		$ 488		$ 574
CET Electric
Schedule of Equity Method Investments [Line Items]
Ownership interest, percentage		45.70%	45.70%
CET Electric | Equity Method Investee | Purchase Price of TOTS Project Transfer
Schedule of Equity Method Investments [Line Items]
Purchase price	$ 122
CET Electric | Equity Method Investee | TOTS Project, Lease Payments
Schedule of Equity Method Investments [Line Items]
Payment for easement rights	$ 8
CET Electric | NY Transco
Schedule of Equity Method Investments [Line Items]
Equity method investment		$ 51

Acquisitions, Investments an137

Acquisitions, Investments and Dispositions - Stagecoach Gas Services (Details) - USD ($) $ in Millions	1 Months Ended
	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Equity method investment		$ 488	$ 574
Stagecoach Gas Services
Schedule of Equity Method Investments [Line Items]
Percentage of equity interest acquired	50.00%
Payments to acquire equity interest	$ 974
Equity method investment		$ 992

Acquisitions, Investments an138

Acquisitions, Investments and Dispositions - Pilesgrove (Details) $ in Millions	1 Months Ended		9 Months Ended
	Aug. 31, 2016USD ($)	Jun. 30, 2016USD ($)	Sep. 30, 2016MW	Dec. 31, 2016USD ($)
Pilesgrove
Business Acquisition [Line Items]
Percentage of voting interest acquired	50.00%
Purchase price	$ 16
Bargain purchase gain	8
Bargain purchase gain, net of taxes	5
Non-utility property	45
Other current assets	$ 3
Pilesgrove | New Jersey
Business Acquisition [Line Items]
Net assets				$ 45
Pilesgrove
Business Acquisition [Line Items]
Equity method investment, impairment charge		$ 8
Equity method investment, impairment charge, net of taxes		$ 5
Percentage of equity interest owned		50.00%
Pilesgrove | New Jersey
Business Acquisition [Line Items]
Generating capacity (MW AC) | MW			18

Acquisitions, Investments an139

Acquisitions, Investments and Dispositions - Panoche Valley (Details) - Panoche Valley - California $ in Millions	1 Months Ended
	Oct. 31, 2016USD ($)MW	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Percentage of equity interest owned	50.00%
Percentage of voting interest acquired	50.00%
Generating capacity (MW AC) | MW	240
Cash consideration	$ 28
Outstanding note payable relieved at acquisition	242
Non-utility construction work in progress	290
Other assets	22
Current liabilities	$ 14
Net assets		$ 388

Acquisitions, Investments an140

Acquisitions, Investments and Dispositions - Coram Wind (Details) - Coram Wind - California $ in Millions	1 Months Ended
	Dec. 31, 2016USD ($)MW
Business Acquisition [Line Items]
Percentage of voting interest acquired	100.00%
Generating capacity (MW AC) | MW	102
Purchase price	$ 97
Non-utility property	191
Intangible assets	78
Restricted cash, current	8
Long-term debt	180
Net assets	$ 96

Acquisitions, Investments an141

Acquisitions, Investments and Dispositions - Pike County Light & Power Company (Details) - Pike - USD ($) $ in Millions	Sep. 30, 2015	Aug. 31, 2016	Dec. 31, 2015
Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of business		$ 15
Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment charge on assets held for sale	$ 5		$ 5
Impairment of long-lived assets to be disposed of, net of tax	$ 3
Assets held for sale			23
Liabilities held for sale			$ 5
O&R | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Period for transition services (up to)		18 months
Agreement to purchase and sell, term		3 years
Agreement to purchase and sell, term of extension option		3 years

Acquisitions, Investments an142

Acquisitions, Investments and Dispositions - Con Edison Solutions' Retail Electric Supply Business (Details) - Retail Electric Supply Business - USD ($) $ in Millions	1 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of business	$ 235
Gain on sale of business	104
Gain on sale of business, after tax	56
Gain on sale of derivatives	65
Gain on sale of derivatives, after tax	42
Tax effect of sale, state tax related to change in apportionment of state income taxes	16
Tax effect of sale, state tax related to change in apportionment of state income taxes, net of federal tax	$ 10
Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale		$ 134
Liabilities held for sale		$ 84

Schedule I - Condensed Finan143

Schedule I - Condensed Financial Information - Condensed Statement of Income and Comprehensive Income (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Income Statements,Captions [Line Items]
Interest expense	$ (696)	$ (653)	$ (591)
NET INCOME	1,245	1,193	1,092
Comprehensive Income	$ 1,252	$ 1,204	$ 1,072
Net Income Per Share – Basic (dollars per share)	$ 4.15	$ 4.07	$ 3.73
Net Income Per Share – Diluted (dollars per share)	4.12	4.05	3.71
Dividends Declared Per Share (dollars per share)	$ 2.68	$ 2.60	$ 2.52
Average Number Of Shares Outstanding—Basic (In Millions)	300.4	293	292.9
Average Number Of Shares Outstanding—Diluted (In Millions)	301.9	294.4	294
Consolidated Edison, Inc.
Condensed Income Statements,Captions [Line Items]
Equity in earnings of subsidiaries	$ 1,254	$ 1,195	$ 1,101
Other income (deductions), net of taxes	32	27	19
Interest expense	(41)	(29)	(28)
NET INCOME	1,245	1,193	1,092
Comprehensive Income	$ 1,252	$ 1,204	$ 1,072
Net Income Per Share – Basic (dollars per share)	$ 4.15	$ 4.07	$ 3.73
Net Income Per Share – Diluted (dollars per share)	4.12	4.05	3.71
Dividends Declared Per Share (dollars per share)	$ 2.68	$ 2.60	$ 2.52
Average Number Of Shares Outstanding—Basic (In Millions)	300.4	293	292.9
Average Number Of Shares Outstanding—Diluted (In Millions)	301.9	294.4	294

Schedule I - Condensed Finan144

Schedule I - Condensed Financial Information - Condensed Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Cash Flow Statements, Captions [Line Items]
Net Income	$ 1,245	$ 1,193	$ 1,092
Change in Assets:
Income taxes receivable	87	58	(224)
Other – net	54	(27)	316
NET CASH FLOWS FROM OPERATING ACTIVITIES	3,459	3,277	2,831
INVESTING ACTIVITIES
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(4,976)	(3,657)	(2,759)
FINANCING ACTIVITIES
Net proceeds of short-term debt	(475)	729	(651)
Issuance of long-term debt	2,590	1,147	1,850
Retirement of long-term debt	(735)	(500)	(480)
Debt issuance costs	(24)	(15)	(17)
Issuance of common shares for stock plans, net of repurchases	51	1	(10)
Issuance of common shares - public offering	702	0	0
Common stock dividends	(763)	(733)	(739)
NET CASH FLOWS FROM/(USED IN) FINANCING ACTIVITIES	1,345	629	(47)
NET CHANGE FOR THE PERIOD	(172)	249	25
BALANCE AT BEGINNING OF PERIOD	944	699	674
BALANCE AT END OF PERIOD EXCLUDING HELD FOR SALE	776	944	699
CECONY
Condensed Cash Flow Statements, Captions [Line Items]
Net Income	1,056	1,084	1,058
Change in Assets:
Other – net	(11)	38	48
NET CASH FLOWS FROM OPERATING ACTIVITIES	3,038	2,819	2,430
INVESTING ACTIVITIES
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(2,739)	(2,638)	(2,304)
FINANCING ACTIVITIES
Net proceeds of short-term debt	(433)	583	(760)
Issuance of long-term debt	1,300	650	1,850
Retirement of long-term debt	(650)	(350)	(475)
Debt issuance costs	(13)	(7)	(17)
NET CASH FLOWS FROM/(USED IN) FINANCING ACTIVITIES	(440)	17	(114)
NET CHANGE FOR THE PERIOD	(141)	198	12
BALANCE AT BEGINNING OF PERIOD	843	645	633
BALANCE AT END OF PERIOD EXCLUDING HELD FOR SALE	702	843	645
Consolidated Edison, Inc.
Condensed Cash Flow Statements, Captions [Line Items]
Net Income	1,245	1,193	1,092
Equity in earnings of subsidiaries	(1,254)	(1,195)	(1,101)
Change in Assets:
Special deposits	0	0	314
Income taxes receivable	87	58	(224)
Other – net	(152)	(382)	(199)
NET CASH FLOWS FROM OPERATING ACTIVITIES	723	635	642
INVESTING ACTIVITIES
Contributions to subsidiaries	(691)	(15)	(1)
Long term debt receivable from affiliated companies	(900)	0	0
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(1,591)	(15)	(1)
FINANCING ACTIVITIES
Net proceeds of short-term debt	(53)	162	101
Issuance of long-term debt	900	0	0
Retirement of long-term debt	(2)	(2)	(2)
Debt issuance costs	(5)	0	0
Issuance of common shares for stock plans, net of repurchases	51	1	(10)
Issuance of common shares - public offering	702	0	0
Common stock dividends	(763)	(733)	(739)
NET CASH FLOWS FROM/(USED IN) FINANCING ACTIVITIES	830	(572)	(650)
NET CHANGE FOR THE PERIOD	(38)	48	(9)
BALANCE AT BEGINNING OF PERIOD	51	3	12
BALANCE AT END OF PERIOD EXCLUDING HELD FOR SALE	13	51	3
Consolidated Edison, Inc. | CECONY
Condensed Cash Flow Statements, Captions [Line Items]
Dividends received	744	872	712
Consolidated Edison, Inc. | O&R
Condensed Cash Flow Statements, Captions [Line Items]
Dividends received	43	81	40
Consolidated Edison, Inc. | Clean Energy Businesses
Condensed Cash Flow Statements, Captions [Line Items]
Dividends received	$ 10	$ 8	$ 8

Schedule I - Condensed Finan145

Schedule I - Condensed Financial Information - Condensed Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CURRENT ASSETS
Cash and temporary cash investments	$ 776	$ 944	$ 699	$ 674
Accounts receivable – other	1,106	1,052
Income taxes receivable	79	166
Prepayments	159	177
Other current assets	205	194
TOTAL CURRENT ASSETS	3,406	3,836
Investments in subsidiaries	1,921	884
Goodwill	428	429
Other noncurrent assets	7,712	8,713
TOTAL ASSETS	48,255	45,642	44,071
CURRENT LIABILITIES
Long-term debt due within one year	39	739
Notes payable	1,054	1,529
Accounts Payable	1,147	1,008
Accrued taxes	64	62
Other current liabilities	297	335
TOTAL CURRENT LIABILITIES	3,843	4,720
Long-term debt	14,735	12,006
Shareholders’ Equity
Equity	14,298	13,052
TOTAL LIABILITIES AND EQUITY	48,255	45,642
Consolidated Edison, Inc.
CURRENT ASSETS
Cash and temporary cash investments	13	51	$ 3	$ 12
Special deposits	1	1
Accounts receivable – other	0	4
Income taxes receivable	79	166
Accounts receivable from affiliated companies	702	517
Prepayments	24	34
Other current assets	18	17
TOTAL CURRENT ASSETS	837	790
Investments in subsidiaries	13,991	12,737
Goodwill	406	406
Deferred income tax	42	11
Long term debt receivable from affiliated companies	900	0
Other noncurrent assets	16	7
TOTAL ASSETS	16,192	13,951
CURRENT LIABILITIES
Long-term debt due within one year	2	2
Notes payable	384	437
Accounts Payable	1	0
Accounts payable to affiliated companies	288	146
Accrued taxes	7	0
Other current liabilities	14	10
TOTAL CURRENT LIABILITIES	696	595
Total Liabilities	696	595
Long-term debt	1,198	304
Shareholders’ Equity
Common stock, including additional paid-in capital	5,887	5,062
Retained earnings	8,411	7,990
Equity	14,298	13,052
TOTAL LIABILITIES AND EQUITY	$ 16,192	$ 13,951

Schedule II - Valuation and 146

Schedule II - Valuation and Qualifying Accounts (Details) - Allowance For Uncollectible Accounts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 96	$ 106	$ 103
Charged To Costs And Expenses	63	77	98
Charged To Other Accounts	0	0	0
Deductions	76	87	95
Balance At End of Period	83	96	106
CECONY
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	91	98	95
Charged To Costs And Expenses	57	69	91
Charged To Other Accounts	0	0	0
Deductions	70	76	88
Balance At End of Period	$ 78	$ 91	$ 98