Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Significant Accounting Policies

Schedule of primary components of accrual revenues

	Activity
Component of Accrual Revenues	Nonregulated Physical Energy Delivery	Regulated Electricity and Gas Sales	Other Nonregulated Products and Services
Gross amounts receivable for sales of products or services based on contract, tariff, or spot price	X	X	X
Reclassification of net gains/losses on cash flow hedges from AOCI	X
Ineffective portion of net gains/losses on cash flow hedges	X
Amortization of acquired energy contract assets or liabilities	X
Recovery or refund of deferred SOS and gas cost adjustment clause regulatory assets/liabilities		X

Schedule of primary components of accrual purchased fuel and energy expense

	Activity
Component of Accrual Fuel and Purchased Energy Expense	Nonregulated Physical Energy Delivery	Regulated Electricity and Gas Sales	Other Nonregulated Products and Services
Actual costs of fuel and purchased energy	X	X	X
Reclassification of net gains/losses on cash flow hedges from AOCI	X
Ineffective portion of net gains/losses on cash flow hedges	X
Amortization of acquired energy contract assets or liabilities	X
Deferral or amortization of deferred SOS and gas cost adjustment clause regulatory assets/liabilities		X

Schedule of permissible accounting treatments for derivatives and effects on financial statements

	Recognition and Measurement
Accounting Treatment
	Balance Sheet	Income Statement
Mark-to-market	•  Derivative asset or liability recorded at fair value	•  Changes in fair value recognized in earnings
Cash flow hedge	•  Derivative asset or liability recorded at fair value •  Effective changes in fair value recognized in accumulated other comprehensive income	•  Ineffective changes in fair value recognized in earnings •  Amounts in accumulated other comprehensive income reclassified to earnings when the hedged forecasted transaction affects earnings or becomes probable of not occurring
Fair value hedge	•  Derivative asset or liability recorded at fair value •  Book value of hedged asset or liability adjusted for changes in its fair value	•  Changes in fair value recognized in earnings •  Changes in fair value of hedged asset or liability recognized in earnings
NPNS (accrual)	•  Fair value not recorded •  Accounts receivable or accounts payable recorded when derivative settles	•  Changes in fair value not recognized in earnings •  Revenue or expense recognized in earnings when underlying physical commodity is sold or consumed

Taxes other than income taxes included in revenues

Year Ended December 31,	2011		2010		2009
	(In millions)
Constellation Energy (including BGE)	$	142.7	$	122.2	$	106.8
BGE		82.9		81.9		76.8

Schedule of non-dilutive stock options and dilutive common stock equivalent shares

Year Ended December 31,	2011		2010		2009
	(In millions)
Non-dilutive stock options		4.3		5.6		5.1
Dilutive common stock equivalent shares		1.8		1.6		1.0

Schedule of estimated useful lives of assets other than electric generating, transmission and distribution, gas distribution facilities and oil and gas exploitation and production activities

Asset	Estimated Useful Lives
Building and improvements	3 - 50 years
Office equipment and furniture	3 - 21 years
Transportation equipment	5 - 15 years
Computer software	3 - 15 years