CONSOLIDATED BALANCE SHEETS (Parenthetical) (Constellation Energy Group, Inc. and Subsidiaries) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowance for uncollectibles	$ 84.9	$ 85.0
Accounts receivable-consolidated variable interest entities, allowance for uncollectibles	95.7	87.9
Unamortized energy contract assets related to CENG	$ 210.4	$ 400.9

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 4
-Article 5

Name:	us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant