Schedule I - Condensed Financial Information - Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Cash Flow Statements, Captions [Line Items]
Net Income	$ 1,346	$ 1,101	$ 1,343
Change in Assets:
Taxes receivable	13	(6)	29
Other – net (b)	(103)	(134)	54
NET CASH FLOWS FROM OPERATING ACTIVITIES	2,733	2,198	3,134
INVESTING ACTIVITIES
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(3,484)	(4,224)	(3,782)
FINANCING ACTIVITIES
Net proceeds of short-term debt	(382)	178	(874)
Issuance of long-term debt	2,804	2,925	3,017
Retirement of long-term debt	(1,960)	(518)	(1,195)
Debt issuance costs	(40)	(47)	(32)
Issuance of common shares for stock plans	60	58	54
Issuance of common shares - public offering	775	640	825
Common stock dividends	(1,030)	(975)	(924)
NET CASH FLOWS FROM FINANCING ACTIVITIES	461	2,245	859
NET CHANGE FOR THE PERIOD	(290)	219	211
BALANCE AT BEGINNING OF PERIOD	1,436	1,217	1,006
BALANCE AT END OF PERIOD	1,146	1,436	1,217
CECONY
Condensed Cash Flow Statements, Captions [Line Items]
Net Income	1,344	1,185	1,250
Change in Assets:
Other – net (b)	(85)	(49)	54
NET CASH FLOWS FROM OPERATING ACTIVITIES	2,186	1,693	2,502
INVESTING ACTIVITIES
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(3,729)	(3,416)	(3,124)
FINANCING ACTIVITIES
Net proceeds of short-term debt	(299)	523	(55)
Issuance of long-term debt	2,250	2,200	1,300
Retirement of long-term debt	(640)	(350)	(475)
Debt issuance costs	(27)	(34)	(21)
NET CASH FLOWS FROM FINANCING ACTIVITIES	1,396	1,857	737
NET CHANGE FOR THE PERIOD	(147)	134	115
BALANCE AT BEGINNING OF PERIOD	1,067	933	818
BALANCE AT END OF PERIOD	920	1,067	933
Parent Company
Condensed Cash Flow Statements, Captions [Line Items]
Net Income	1,346	1,101	1,343
Equity in earnings of subsidiaries	(1,369)	(1,105)	(1,354)
Change in Assets:
Special deposits	0	0	(3)
Taxes receivable	15		25
Other – net (b)	211	(521)	44
NET CASH FLOWS FROM OPERATING ACTIVITIES	1,459	538	1,029
INVESTING ACTIVITIES
Contributions to subsidiaries	(1,135)	(626)	(930)
Debt receivable from affiliated companies	875	400	450
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(260)	(226)	(480)
FINANCING ACTIVITIES
Net proceeds of short-term debt	50	(537)	(783)
Issuance of long-term debt	0	650	825
Retirement of long-term debt	(1,178)	(3)	(553)
Debt issuance costs	(1)	(3)	0
Issuance of common shares for stock plans	60	58	54
Issuance of common shares - public offering	775	640	825
Common stock dividends	(1,030)	(975)	(924)
NET CASH FLOWS FROM FINANCING ACTIVITIES	(1,324)	(170)	(556)
NET CHANGE FOR THE PERIOD	(125)	142	(7)
BALANCE AT BEGINNING OF PERIOD	144	2	9
BALANCE AT END OF PERIOD	19	144	2
Parent Company | Revision of Prior Period, Adjustment
FINANCING ACTIVITIES
Retirement of long-term debt	(1,175)
Parent Company | CECONY
Condensed Cash Flow Statements, Captions [Line Items]
Dividends received	988	982	912
Parent Company | O&R
Condensed Cash Flow Statements, Captions [Line Items]
Dividends received	52	49	47
Parent Company | Clean Energy Businesses
Condensed Cash Flow Statements, Captions [Line Items]
Dividends received	64	21	3
Parent Company | Con Edison Transmission
Condensed Cash Flow Statements, Captions [Line Items]
Dividends received	$ 152	$ 11	$ 12