Consolidated Balance Sheet (Parenthetical) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Accounts receivable - customers, allowance for uncollectible accounts	$ 88	$ 76
Other receivables, allowance for uncollectible accounts	9	8
Non-utility property, accumulated depreciation	57	51
Intangible assets, accumulated amortization	3	3
CECONY [Member]
Accounts receivable - customers, allowance for uncollectible accounts	80	68
Other receivables, allowance for uncollectible accounts	8	7
Non-utility property, accumulated depreciation	$ 23	$ 22