XML 154 R120.htm IDEA: XBRL DOCUMENT v2.4.0.6
Quarterly Financial Information (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 12 Months Ended
Jun. 30, 2011
Dec. 31, 2010
Sep. 30, 2010
Jun. 30, 2010
Mar. 31, 2010
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Quarterly Financial Information [Abstract]                
Gain on early termination of finance leases held in trust $ 39         $ 39    
Gain on early termination of leases, after tax 3         3    
Reversal of previously recognized tax benefits for federal liabilities 22              
Reversal of previously recognized tax benefits on early termination of cross-border energy leases (14)              
Restructuring Charges   16 14       30  
Effects of Pepco divestiture-related claims     9 2     11 (40)
Loss on extinguishment of debt   (54) (135)       (189)  
Interest income reversal   11     8 37 11  
Deferred Tax Asset Related to Medicare Part D         4      
State income tax benefit   4 13 8 8      
Federal income tax benefit   $ 18