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