Fair Value of Financial Assets and Liabilities (Tables)

6 Months Ended

Jun. 30, 2013

Fair value of financial liabilities recorded at the carrying amount

	June 30, 2013
	Carrying		Fair Value
	Amount		Level 1		Level 2		Level 3		Total
Short-term liabilities	$	875	$	3	$	872	$	-	$	875
Long-term debt (including amounts due within one year)		18,601		-		18,926		461		19,387
Long-term debt to financing trusts		648		-		-		650		650
SNF obligation		1,020		-		777		-		777

	December 31, 2012
	Carrying		Fair Value
	Amount		Level 1		Level 2		Level 3		Total
Short-term liabilities	$	214	$	4	$	210	$	-	$	214
Long-term debt (including amounts due within one year)		18,745		-		20,244		276		20,520
Long-term debt to financing trusts		648		-		-		664		664
SNF obligation		1,020		-		763		-		763
Preferred securities of subsidiary		87		-		82		-		82

Assets and liabilities measured and recorded at fair value on recurring basis

As of June 30, 2013	Level 1		Level 2		Level 3			Total
Assets
Cash equivalents(a)	$	589	$	0	$	0		$	589
Nuclear decommissioning trust fund investments
Cash equivalents		229		0		0			229
Equity
Individually held		1,691		0		0			1,691
Commingled funds		0		2,071		0			2,071
Equity funds subtotal		1,691		2,071		0			3,762
Fixed income
Debt securities issued by the U.S. Treasury and other
U.S. government corporations and agencies		966		0		0			966
Debt securities issued by states of the United States
and political subdivisions of the states		0		314		0			314
Debt securities issued by foreign governments		0		85		0			85
Corporate debt securities		0		1,727		0			1,727
Federal agency mortgage-backed securities		0		18		0			18
Commercial mortgage-backed securities (non-agency)		0		41		0			41
Residential mortgage-backed securities (non-agency)		0		10		0			10
Mutual funds		0		37		0			37
Fixed income subtotal		966		2,232		0			3,198
Middle market lending		0		0		240			240
Other debt obligations		0		12		0			12
Nuclear decommissioning trust fund investments subtotal(b)		2,886		4,315		240			7,441

Pledged assets for Zion Station decommissioning
Cash equivalents		0		62		0			62
Equity
Individually held		1		0		0			1
Equity funds subtotal		1		0		0			1
Fixed income
Debt securities issued by the U.S. Treasury and other
U.S. government corporations and agencies		143		8		0			151
Debt securities issued by states of the United States
and political subdivisions of the states		0		27		0			27
Corporate debt securities		0		193		0			193
Federal agency mortgage-backed securities		0		17		0			17
Commercial mortgage-backed securities (non-agency)		0		1		0			1
Fixed income subtotal		143		246		0			389
Middle market lending		0		0		111			111
Other debt obligations		0		3		0			3
Pledged assets for Zion Station decommissioning subtotal(c)		144		311		111			566

Rabbi trust investments
Cash equivalents		2		0		0			2
Mutual funds(d)(e)		67		0		0			67
Rabbi trust investments subtotal		69		0		0			69

Commodity mark-to-market derivative assets
Economic hedges		721		2,659		676			4,056
Proprietary trading		839		1,445		162			2,446
Effect of netting and allocation of collateral(f)		(1,645)		(3,087)		(226)			(4,958)
Commodity mark-to-market assets subtotal		(85)		1,017		612			1,544

Interest rate mark-to-market derivative assets		36		74		0			110
Effect of netting and allocation of collateral		(36)		(1)		0			(37)
Interest rate mark-to-market derivative assets subtotal		0		73		0			73

Other investments		1		0		11			12

Total assets		3,604		5,716		974			10,294

Liabilities
Commodity mark-to-market derivative liabilities
Economic hedges		(977)		(1,974)		(276)			(3,227)
Proprietary trading		(855)		(1,371)		(141)			(2,367)
Effect of netting and allocation of collateral(f)		1,833		3,217		236			5,286
Commodity mark-to-market liabilities subtotal(h)		1		(128)		(181)			(308)

Interest rate mark-to-market derivative liabilities		(36)		(18)		0	0		(54)
Effect of netting and allocation of collateral		36		1		0			37
Interest rate mark-to-market derivative liabilities subtotal		0		(17)		0			(17)

Deferred compensation obligation		0		(105)		0			(105)

Total liabilities		1		(250)		(181)			(430)

Total net assets	$	3,605	$	5,466	$	793		$	9,864

As of December 31, 2012	Level 1		Level 2		Level 3			Total
Assets
Cash equivalents(a)	$	995	$	0	$	0		$	995
Nuclear decommissioning trust fund investments
Cash equivalents		245		0		0			245
Equity
Individually held		1,480		0		0			1,480
Commingled funds		0		1,933		0			1,933
Equity funds subtotal		1,480		1,933		0			3,413
Fixed income
Debt securities issued by the U.S. Treasury and other
U.S. government corporations and agencies		1,057		0		0			1,057
Debt securities issued by states of the United States
and political subdivisions of the states		0		321		0			321
Debt securities issued by foreign governments		0		93		0			93
Corporate debt securities		0		1,788		0			1,788
Federal agency mortgage-backed securities		0		24		0			24
Commercial mortgage-backed securities (non-agency)		0		45		0			45
Residential mortgage-backed securities (non-agency)		0		11		0			11
Mutual funds		0		23		0			23
Fixed income subtotal		1,057		2,305		0			3,362
Middle market lending		0		0		183			183
Other debt obligations		0		15		0			15
Nuclear decommissioning trust fund investments subtotal(b)		2,782		4,253		183			7,218

Pledged assets for Zion decommissioning
Cash equivalents		0		23		0			23
Equity
Individually held		14		0		0			14
Commingled funds		0		9		0			9
Equity funds subtotal		14		9		0			23
Fixed income
Debt securities issued by the U.S. Treasury and other
U.S. government corporations and agencies		118		12		0			130
Debt securities issued by states of the United States
and political subdivisions of the states		0		37		0			37
Corporate debt securities		0		249		0			249
Federal agency mortgage-backed securities		0		49		0			49
Commercial mortgage-backed securities (non-agency)		0		6		0			6
Fixed income subtotal		118		353		0			471
Middle market lending		0		0		89			89
Other debt obligations		0		1		0			1
Pledged assets for Zion Station decommissioning subtotal(c)		132		386		89			607

Rabbi trust investments
Cash equivalents		2		0		0			2
Mutual funds(d)(e)		69		0		0			69
Rabbi trust investments subtotal		71		0		0			71

Commodity mark-to-market derivative assets
Cash flow hedges		0		0		0			0
Economic hedges		861		3,173		641			4,675
Proprietary trading		1,042		2,078		73			3,193
Effect of netting and allocation of collateral(f)		(1,823)		(4,175)		(58)			(6,056)
Commodity mark-to-market assets subtotal(g)		80		1,076		656			1,812

Interest rate mark-to-market derivative assets		0		114		0			114
Effect of netting and allocation of collateral		0		(51)		0			(51)
Interest rate mark-to-market derivative assets subtotal		0		63		0			63

Other Investments		2		0		17			19
Total assets		4,062		5,778		945			10,785

Liabilities
Commodity mark-to-market derivative liabilities
Economic hedges		(1,041)		(2,289)		(236)			(3,566)
Proprietary trading		(1,084)		(1,959)		(78)			(3,121)
Effect of netting and allocation of collateral(f)		2,042		4,020		25			6,087
Commodity mark-to-market liabilities subtotal(g)(h)		(83)		(228)		(289)			(600)

Interest rate mark-to-market derivative liabilities		0		(84)		0			(84)
Effect of netting and allocation of collateral		0		51		0			51
Interest rate mark-to-market derivative liabilities subtotal		0		(33)		0			(33)

Deferred compensation obligation		0		(102)		0			(102)

Total liabilities		(83)		(363)		(289)			(735)

Total net assets	$	3,979	$	5,415	$	656		$	10,050

(a) Excludes certain cash equivalents considered to be held-to-maturity and not reported at fair value.

(b) Excludes net assets of $22 million and $30 million at June 30, 2013 and December 31, 2012, respectively. These items consist of receivables related to pending securities sales, interest and dividend receivables, and payables related to pending securities purchases.

(c) Excludes net (liabilities) assets of $ (28) million and $7 million at June 30, 2013 and December 31, 2012, respectively. These items consist of receivables related to pending securities sales, interest and dividend receivables, and payables related to pending securities purchases.

(d) The mutual funds held by the Rabbi trusts include $51 million related to deferred compensation and $16 million related to Supplemental Executive Retirement Plan at June 30, 2013, and $53 million related to deferred compensation and $16 million related to Supplemental Executive Retirement Plan at December 31, 2012. These funds are classified as Level 1 as they are valued based upon quoted prices (unadjusted) in active markets.

(e) Excludes $29 million and $28 million of the cash surrender value of life insurance investments at June 30, 2013 and December 31, 2012, respectively.

(f) Includes collateral postings (received) from counterparties. Collateral (received) from counterparties, net of collateral paid to counterparties, totaled $188 million, $130 million and $10 million allocated to Level 1, Level 2 and Level 3 mark-to-market derivatives, respectively, as of June 30, 2013. Collateral (received) from counterparties, net of collateral paid to counterparties, totaled $219 million, $(155) million and $(33) million allocated to Level 1, Level 2 and Level 3 mark-to-market derivatives, respectively, as of December 31, 2012.

(g) The Level 3 balance does not include current assets for Generation and current liabilities for ComEd of $226 million at December 31, 2012, related to the fair value of Generation's financial swap contract with ComEd.

(h) The Level 3 balance includes the current and noncurrent liability of $16 million and $69 million at June 30, 2013, respectively, and $18 million and $49 million at December 31, 2012, respectively, related to floating-to-fixed energy swap contracts with unaffiliated suppliers.

Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis

Three Months Ended June 30, 2013		Nuclear Decommissioning Trust Fund Investments		Pledged Assets for Zion Station Decommissioning		Mark-to-Market Derivatives			Other Investments		Total
Balance as of March 31, 2013		$	210	$	104	$	260		$	9	$	583
Total realized / unrealized gains (losses)
	Included in net income		1		0		158	(a)		0		159
	Included in other comprehensive income		0		0		0			0		0
	Included in regulatory assets		8		0		(10)	(b)		0		(2)
	Included in payable for Zion Station decommissioning		0		1		0			0		1
Change in collateral			0		0		10			0		10
Purchases, sales, issuances and settlements
	Purchases		35		11		13			2		61
	Sales		(11)		(5)		(4)			0		(20)
	Settlements		(3)		0		0			0		(3)
Transfers into Level 3			0		0		3			0		3
Transfers out of Level 3			0		0		1			0		1

Balance as of June 30, 2013		$	240	$	111	$	431		$	11	$	793
The amount of total gains included in income
	attributed to the change in unrealized gains (losses) related to assets and liabilities held for the three months ended June 30, 2013	$	1	$	0	$	187		$	0	$	188

Six Months Ended June 30, 2013		Nuclear Decommissioning Trust Fund Investments		Pledged Assets for Zion Station Decommissioning		Mark-to-Market Derivatives			Other Investments		Total
Balance as of December 31, 2012		$	183	$	89	$	367		$	17	$	656
Total realized / unrealized gains (losses)
	Included in net income		2		0		31	(a)		0		33
	Included in other comprehensive income		0		0		0			0		0
	Included in regulatory assets		9		0		(18)	(b)		0		(9)
	Included in payable for Zion Station decommissioning		0		1		0			0		1
Change in collateral			0		0		43			0		43
Purchases, sales, issuances and settlements
	Purchases		67		33		8	(c)		2		110
	Sales		(13)		(12)		(8)			(8)		(41)
	Settlements		(8)		0		0			0		(8)
Transfers into Level 3			0		0		7			0		7
Transfers out of Level 3			0		0		1			0		1

Balance as of June 30, 2013		$	240	$	111	$	431		$	11	$	793
The amount of total gains included in income
	attributed to the change in unrealized gains (losses) related to assets and liabilities held for the six months ended June 30, 2013	$	1	$	0	$	108		$	0	$	109

(a) Includes the reclassification of $29 million and $77 million of realized losses due to the settlement of derivative contracts recorded in results of operations for the three and six months ended June 30, 2013.

(b) Excludes decreases in fair value of $3 million and $11 million and realized losses reclassified due to settlements of $82 million and $215 million associated with Generation's financial swap contract with ComEd for the three and six months ended June 30, 2013. All items eliminate upon consolidation in Exelon's Consolidated Financial Statements.

Three Months Ended June 30, 2012		Nuclear Decommissioning Trust Fund Investments		Pledged Assets for Zion Station Decommissioning		Mark-to-Market Derivatives			Other Investments		Total
Balance as of March 31, 2012		$	13	$	42	$	359		$	14	$	428
Total realized / unrealized gains (losses)
	Included in net income		0		0		(64)	(a)		0		(64)
	Included in other comprehensive income		0		0		0			0		0
	Included in regulatory assets		0		0		30	(b)		0		30
	Included in payable for Zion Station
	decommissioning		0		(1)		0			0		(1)
Change in collateral			0		0		44			0		44
Purchases, sales, issuances and settlements
	Purchases		41		26		0			3		70
	Sales		0		(8)		0			0		(8)
Transfers into Level 3			0		0		(34)			0		(34)
Transfers out of Level 3			0		0		(40)			0		(40)

Balance as of June 30, 2012		$	54	$	59	$	295		$	17	$	425
The amount of total gains included in income
	attributed to the change in unrealized losses related to assets and liabilities held for the three months ended June 30, 2012	$	0	$	0	$	2		$	0	$	2

Six Months Ended June 30, 2012		Nuclear Decommissioning Trust Fund Investments		Pledged Assets for Zion Decommissioning		Mark-to-Market Derivatives			Other Investments		Total
Balance as of December 31, 2011		$	13	$	37	$	17		$	0	$	67
Total realized / unrealized gains (losses)
	Included in net income		0		0		19	(a)		0		19
	Included in other comprehensive income		0		0		0			0		0
	Included in regulatory assets		0		0		(5)	(b)		0		(5)
	Included in payable for Zion Station
	decommissioning		0		(1)		0			0		(1)
Change in collateral			0		0		8			0		8
Purchases, sales, issuances and settlements
	Purchases		41		32		329	(c)		17		419
	Sales		0		(9)		0			0		(9)
Transfers into Level 3			0		0		(34)			0		(34)
Transfers out of Level 3			0		0		(39)			0		(39)

Balance as of June 30, 2012		$	54	$	59	$	295		$	17	$	425
The amount of total gains included in income
	attributed to the change in unrealized gains (losses) related to assets and liabilities held for the six months ended June 30, 2012	$	0	$	0	$	104		$	0	$	104

(a) Includes the reclassification of $66 million and $85 million of realized losses due to the settlement of derivative contracts recorded in results of operations for the three and six months ended June 30, 2012, respectively.

(b) Excludes $14 million and $121 million of decreases in fair value and $161 million and $308 million of realized losses due to settlements for the three and six months ended June 30, 2012 of Generation's financial swap contract with ComEd, which eliminates upon consolidation in Exelon's Consolidated Financial Statements.

Total realized and unrealized gains (losses) included in income for Level 3 assets and liabilities measured at fair value on a recurring basis


		Operating Revenue		Purchased Power and Fuel		Other, net (a)

Total gains included in income for the three months ended
	June 30, 2013	$	137	$	21	$	1
Total gains (losses) included in income for the six months ended
	June 30, 2013	$	(22)	$	53	$	2
Change in the unrealized gains relating to assets and liabilities
	held for the three months ended June 30, 2013	$	156	$	31	$	1
Change in the unrealized gains relating to assets and liabilities
	held for the six months ended June 30, 2013	$	39	$	69	$	1

		Operating Revenue		Purchased Power and Fuel		Other, net
Total gains (losses) included in income for the three months
	ended June 30, 2012	$	(69)	$	5	$	-
Total gains (losses) included in income for the six months ended
	June 30, 2012	$	23	$	(4)	$	-
Change in the unrealized gains (losses) relating to assets and
	liabilities held for the three months ended June 30, 2012	$	5	$	(3)	$	-
Change in the unrealized gains (losses) relating to assets and
	liabilities held for the six months ended June 30, 2012	$	125	$	(21)	$	-

Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis, valuation technique

Type of trade	Fair Value at June 30, 2013 (c)		Valuation Technique	Unobservable Input	Range
Mark-to-market derivatives – Economic Hedges (Generation) (a)	$	485	Discounted Cash Flow	Forward power price	$	15		-	$	87
			Discounted Cash Flow	Forward gas price	$	3.54		-	$	4.72
			Option Model	Volatility percentage		28	%	-		363	%

Mark-to-market derivatives – Proprietary trading (Generation) (a)	$	21	Discounted Cash Flow	Forward power price	$	16		-	$	87
			Option Model	Volatility percentage		11	%	-		23	%

Mark-to-market derivatives (ComEd)	$	(85)	Discounted Cash Flow	Forward heat rate (b)		8	%	-		9	%
				Marketability reserve		3.5	%	-		8	%
				Renewable factor		85	%	-		129	%

Type of trade	Fair Value at December 31, 2012 (d)		Valuation Technique	Unobservable Input	Range
Mark-to-market derivatives – Economic Hedges (Generation) (a)	$	473	Discounted Cash Flow	Forward power price	$	14		-	$	79
			Discounted Cash Flow	Forward gas price	$	3.26		-	$	6.27
			Option Model	Volatility percentage		28	%	-		132	%

Mark-to-market derivatives – Proprietary trading (Generation) (a)	$	(6)	Discounted Cash Flow	Forward power price	$	15		-	$	106
			Option Model	Volatility percentage		16	%	-		48	%

Mark-to-market derivatives - Transactions with Affiliates (Generation and ComEd) (b)	$	226	Discounted Cash Flow	Marketability reserve		8	%	-		9	%

Mark-to-market derivatives (ComEd)	$	(67)	Discounted Cash Flow	Forward heat rate (c)		8	%	-		9.5	%
				Marketability reserve		3.5	%	-		8.3	%
				Renewable factor		81	%	-		123	%

The valuation techniques, unobservable inputs and ranges are the same for the asset and liability positions.
Includes current assets for Generation and current liabilities for ComEd of $226 million, related to the fair value of the five-year financial swap contract between Generation and ComEd, which eliminates in consolidation.
Quoted forward natural gas rates are utilized to project the forward power curve for the delivery of energy at specified future dates. The natural gas curve is extrapolated beyond its observable period to the end of the contract's delivery.
The fair values do not include cash collateral held on level three positions of $33 million as of December 31, 2012.

Exelon Generation Co L L C [Member]

Fair Value Tables [Line Items]

Fair value of financial liabilities recorded at the carrying amount

	June 30, 2013
	Carrying		Fair Value
	Amount		Level 1		Level 2		Level 3		Total
Short-term liabilities	$	288	$	0	$	288	$	0	$	288
Long-term debt (including amounts due within one year)		7,213		0		6,817		443		7,260
SNF obligation		1,020		0		777		0		777

	December 31, 2012
	Carrying		Fair Value
	Amount		Level 1		Level 2		Level 3		Total
Long-term debt (including amounts due within one year)	$	7,483	$	0	$	7,591	$	258	$	7,849
SNF obligation		1,020		0		763		0		763

Assets and liabilities measured and recorded at fair value on recurring basis

As of June 30, 2013	Level 1		Level 2		Level 3			Total
Assets
Cash equivalents	$	45	$	0	$	0	$	45
Nuclear decommissioning trust fund investments
Cash equivalents		229		0		0		229
Equity
Individually held		1,691		0		0		1,691
Commingled funds		0		2,071		0		2,071
Equity funds subtotal		1,691		2,071		0		3,762
Fixed income
Debt securities issued by the U.S. Treasury and other U.S.
government corporations and agencies		966		0		0		966
Debt securities issued by states of the United States and
political subdivisions of the states		0		314		0		314
Debt securities issued by foreign governments		0		85		0		85
Corporate debt securities		0		1,727		0		1,727
Federal agency mortgage-backed securities		0		18		0		18
Commercial mortgage-backed securities (non-agency)		0		41		0		41
Residential mortgage-backed securities (non-agency)		0		10		0		10
Mutual funds		0		37		0		37
Fixed income subtotal		966		2,232		0		3,198
Middle market lending		0		0		240		240
Other debt obligations		0		12		0		12
Nuclear decommissioning trust fund investments subtotal(b)		2,886		4,315		240		7,441

Pledged assets for Zion Station decommissioning
Cash equivalents		0		62		0		62
Equity
Individually held		1		0		0		1
Equity funds subtotal		1		0		0		1
Fixed income
Debt securities issued by the U.S. Treasury and other U.S.
government corporations and agencies		143		8		0		151
Debt securities issued by states of the United States and
political subdivisions of the states		0		27		0		27
Corporate debt securities		0		193		0		193
Federal agency mortgage-backed securities		0		17		0		17
Commercial mortgage-backed securities (non-agency)		0		1		0		1
Fixed income subtotal		143		246		0		389
Middle market lending		0		0		111		111
Other debt obligations		0		3		0		3
Pledged assets for Zion Station decommissioning subtotal(c)		144		311		111		566

Rabbi trust investments
Mutual funds(d)(e)		13		0		0		13
Rabbi trust investments subtotal		13		0		0		13

Commodity mark-to-market derivative assets
Economic hedges		721		2,659		676		4,056
Proprietary trading		839		1,445		162		2,446
Effect of netting and allocation of collateral(f)		(1,645)		(3,087)		(226)		(4,958)
Commodity mark-to-market assets subtotal		(85)		1,017		612		1,544

Interest rate mark-to-market derivative assets		36		42		0		78
Effect of netting and allocation of collateral		(36)		(1)		0		(37)
Interest rate mark-to-market derivative assets subtotal		0		41		0		41

Other investments		1		0		11		12

Total assets		3,004		5,684		974		9,662

Liabilities
Commodity mark-to-market derivative liabilities
Economic hedges		(977)		(1,974)		(191)		(3,142)
Proprietary trading		(855)		(1,371)		(141)		(2,367)
Effect of netting and allocation of collateral(f)		1,833		3,217		236		5,286
Commodity mark-to-market liabilities subtotal		1		(128)		(96)		(223)

Interest rate mark-to-market derivative liabilities		(36)		(18)		0		(54)
Effect of netting and allocation of collateral		36		1		0		37
Interest rate mark-to-market derivative liabilities subtotal		0		(17)		0		(17)

Deferred compensation obligation		0		(25)		0		(25)

Total liabilities		1		(170)		(96)		(265)

Total net assets	$	3,005	$	5,514	$	878	$	9,397

As of December 31, 2012	Level 1		Level 2		Level 3			Total
Assets
Cash equivalents(a)	$	487	$	0	$	0	$	487
Nuclear decommissioning trust fund investments
Cash equivalents		245		0		0		245
Equity
Individually held		1,480		0		0		1,480
Commingled funds		0		1,933		0		1,933
Equity funds subtotal		1,480		1,933		0		3,413
Fixed income
Debt securities issued by the U.S. Treasury and other U.S.
government corporations and agencies		1,057		0		0		1,057
Debt securities issued by states of the United States and
political subdivisions of the states		0		321		0		321
Debt securities issued by foreign governments		0		93		0		93
Corporate debt securities		0		1,788		0		1,788
Federal agency mortgage-backed securities		0		24		0		24
Commercial mortgage-backed securities (non-agency)		0		45		0		45
Residential mortgage-backed securities (non-agency)		0		11		0		11
Mutual funds		0		23		0		23
Fixed income subtotal		1,057		2,305		0		3,362
Middle market lending		0		0		183		183
Other debt obligations		0		15		0		15
Nuclear decommissioning trust fund investments subtotal(b)		2,782		4,253		183		7,218

Pledged assets for Zion Station decommissioning
Cash equivalents		0		23		0		23
Equity
Individually held		14		0		0		14
Commingled funds		0		9		0		9
Equity funds subtotal		14		9		0		23
Fixed income
Debt securities issued by the U.S. Treasury and other U.S.
government corporations and agencies		118		12		0		130
Debt securities issued by states of the United States and
political subdivisions of the states		0		37		0		37
Corporate debt securities		0		249		0		249
Federal agency mortgage-backed securities		0		49		0		49
Commercial mortgage-backed securities (non-agency)		0		6		0		6
Fixed income subtotal		118		353		0		471
Middle market lending		0		0		89		89
Other debt obligations		0		1		0		1
Pledged assets for Zion Station decommissioning subtotal(c)		132		386		89		607

Rabbi trust investments
Cash equivalents		1		0		0		1
Mutual funds(d)(e)		13		0		0		13
Rabbi trust investments subtotal		14		0		0		14

Commodity mark-to-market derivative assets
Economic hedges		861		3,173		867		4,901
Proprietary trading		1,042		2,078		73		3,193
Effect of netting and allocation of collateral(f)		(1,823)		(4,175)		(58)		(6,056)
Commodity mark-to-market assets subtotal(g)		80		1,076		882		2,038

Interest rate mark-to-market derivative assets		0		101		0		101
Effect of netting and allocation of collateral		0		(51)		0		(51)
Interest rate mark-to-market derivative assets subtotal		0		50		0		50

Other investments		2		0		17		19

Total assets		3,497		5,765		1,171		10,433

Liabilities
Commodity mark-to-market derivative liabilities
Economic hedges		(1,041)		(2,289)		(169)		(3,499)
Proprietary trading		(1,084)		(1,959)		(78)		(3,121)
Effect of netting and allocation of collateral(f)		2,042		4,020		25		6,087
Commodity mark-to-market liabilities subtotal		(83)		(228)		(222)		(533)

Interest rate mark-to-market derivative liabilities		0		(84)		0		(84)
Effect of netting and allocation of collateral		0		51		0		51
Interest rate mark-to-market derivative liabilities		0		(33)		0		(33)

Deferred compensation obligation		0		(28)		0		(28)

Total liabilities		(83)		(289)		(222)		(594)

Total net assets	$	3,414	$	5,476	$	949	$	9,839

(a) Excludes certain cash equivalents considered to be held-to-maturity and not reported at fair value.

(c) Excludes net (liabilities) assets of $ (28) million and $7 million at June 30, 2013 December 31, 2012, respectively. These items consist of receivables related to pending securities sales, interest and dividend receivables, and payables related to pending securities purchases.

(d) The mutual funds held by the Rabbi trusts are classified as Level 1 as they are valued based upon quoted prices (unadjusted) in active markets.

(e) Excludes $9 million and $8 million of the cash surrender value of life insurance investments at June 30, 2013 and December 31, 2012, respectively.

The level 3 balance includes current assets for Generation of $226 million at December 31, 2012, related to the fair value of Generation's financial swap contract with ComEd, which eliminates upon consolidation in Exelon's Consolidated Financial Statements.

Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis

Three Months Ended June 30, 2013		Nuclear Decommissioning Trust Fund Investments			Pledged Assets for Zion Station Decommissioning	Mark-to-Market Derivatives			Other Investments		Total
Balance as of March 31, 2013		$	210	$	104	$	420		$	9	$	743
Total realized / unrealized gains (losses)
	Included in net income		1		-		168	(a)(b)		-		169
	Included in other comprehensive income		-		-		(95)	(b)		-		(95)
	Included in noncurrent payables to affiliates		8		-		-			-		8
	Included in payable for Zion Station decommissioning		-		1		-			-		1
Change in collateral			-		-		10			-		10
Purchases, sales, issuances and settlements
	Purchases		35		11		13			2		61
	Sales		(11)		(5)		(4)			-		(20)
	Settlements		(3)		-		-			-		(3)
Transfers into Level 3			-		-		3			-		3
Transfers out of Level 3			-		-		1			-		1

Balance as of June 30, 2013		$	240	$	111	$	516		$	11	$	878
The amount of total losses included in income
	attributed to the change in unrealized gains (losses) related to assets and liabilities held for the three months ended June 30, 2013	$	1	$	-	$	183		$	-	$	184

Six Months Ended June 30, 2013		Nuclear Decommissioning Trust Fund Investments			Pledged Assets for Zion Station Decommissioning	Mark-to-Market Derivatives			Other Investments		Total
Balance as of December 31, 2012		$	183	$	89	$	660		$	17	$	949
Total realized / unrealized gains (losses)
	Included in net income		2		-		24	(a)(b)		-		26
	Included in other comprehensive income		-		-		(219)	(b)		-		(219)
	Included in noncurrent payables to affiliates		9		-		-			-		9
	Included in payable for Zion Station decommissioning		-		1		-			-		1
Change in collateral					-		43			-		43
Purchases, sales, issuances and settlements
	Purchases		67		33		8	(c)		2		110
	Sales		(13)		(12)		(8)			(8)		(41)
	Settlements		(8)		-		-			-		(8)
Transfers into Level 3			-		-		7					7
Transfers out of Level 3			-		-		1			-		1

Balance as of June 30, 2013		$	240	$	111	$	516		$	11	$	878
The amount of total losses included in income
	attributed to the change in unrealized gains (losses) related to assets and liabilities held for the six months ended June 30, 2013	$	1	$	-	$	97		$	-	$	98

(a) Includes the reclassification of $15 million and $73 million of realized losses due to the settlement of derivative contracts recorded in results of operations for the three and six months ended June 30, 2013, respectively.

(b) Includes $3 million of decreases in fair value and $11 million of increases in fair value and realized losses due to settlements of $82 million and $215 million associated with Generation's financial swap contract with ComEd for the three and six months ended June 30, 2013, respectively. This position eliminates upon consolidation in Exelon's Consolidated Financial Statements.

Three Months Ended June 30, 2012		Nuclear Decommissioning Trust Fund Investments		Pledged Assets for Zion Station Decommissioning		Mark-to-Market Derivatives			Other Investments		Total
Balance as of March 31, 2012		$	13	$	42	$	1,182		$	14	$	1,251
Total realized / unrealized gains (losses)
	Included in net income		0		0		(69)	(a)		0		(69)
	Included in other comprehensive income		0		0		(171)	(b)		0		(171)
	Included in payable for Zion Station decommissioning		0		(1)		0			0		(1)
Changes in collateral			0		0		44			0		44
Purchases, sales, issuances and settlements
	Purchases		41		26		0			3		70
	Sales		0		(8)		0			0		(8)
Transfers into Level 3			0		0		(34)			0		(34)
Transfers out of Level 3			0		0		(40)			0		(40)

Balance as of June 30, 2012		$	54	$	59	$	912		$	17	$	1,042

The amount of total gains included in income
	attributed to the change in unrealized (losses) related to assets and liabilities held for the three months ended June 30, 2012	$	0	$	0	$	(13)		$	0	$	(13)

Six Months Ended June 30, 2012		Nuclear Decommissioning Trust Fund Investments		Pledged Assets for Zion Station Decommissioning		Mark-to-Market Derivatives			Other Investments		Total
Balance as of December 31, 2011		$	13	$	37	$	817		$	0	$	867
Total realized / unrealized gains (losses)
	Included in net income		0		0		3	(a)		0		3
	Included in other comprehensive income		0		0		(172)	(b)		0		(172)
	Included in payable for Zion Station decommissioning		0		(1)		0			0		(1)
Changes in collateral			0		0		8			0		8
Purchases, sales, issuances and settlements												0
	Purchases		41		32		329	(c)		17		419
	Sales		0		(9)		0			0		(9)
Transfers into Level 3			0		0		(34)			0		(34)
Transfers out of Level 3			0		0		(39)			0		(39)

Balance as of June 30, 2012		$	54	$	59	$	912		$	17	$	1,042

The amount of total gains included in income
	attributed to the change in unrealized gains related to assets and liabilities held for the six months ended June 30, 2012	$	0	$	0	$	78		$	0	$	78

(a) Includes the reclassification of $56 million and $75 million of realized losses due to the settlement of derivative contracts recorded in results of operations for the three and six months ended June 30, 2012, respectively.

(b) Includes $14 million of decreases in fair value and $121 million of increases in fair value and realized losses due to settlements of $161 million and $308 million associated with Generation's financial swap contract with ComEd for the three and six months ended June 30, 2012, respectively. This position was re-designated as a cash flow hedge prior to the merger date. All prospective changes in fair value and reclassifications of realized amounts are being recorded to income offset by the amortization of the frozen mark in OCI. All items eliminate upon consolidation in Exelon's Consolidated Financial Statements.

(c) Includes $310 million of fair value from contracts and $14 million of other investments acquired as a result of the merger.

Total realized and unrealized gains (losses) included in income for Level 3 assets and liabilities measured at fair value on a recurring basis

(a) Other, net activity consists of realized and unrealized gains (losses) included in income for the NDT funds held by Generation.

		Operating Revenue		Purchased Power and Fuel		Other, net (a)
Total gains included in net income for the three months ended		$	148	$	20	$	1
	June 30, 2013
Total gains (losses) included in net income for the six months
	ended June 30, 2013	$	(28)	$	52	$	2
Change in the unrealized gains relating to assets and liabilities
	held for the three months ended June 30, 2013	$	153	$	30	$	1
Change in the unrealized gains relating to assets and liabilities
	held for the six months ended June 30, 2013	$	29	$	68	$	1

		Operating Revenue		Purchased Power and Fuel		Other, net
Total gains (losses) included in net income for the three months		$	(74)	$	5	$	-
	ended June 30, 2012
Total gains (losses) included in net income for the six months		$	7	$	(4)	$	-
	ended June 30, 2012
Change in the unrealized gains (losses) relating to assets and		$	(10)	$	(3)	$	-
	liabilities held for the three months ended June 30, 2012
Change in the unrealized gains (losses) relating to assets and liabilities		$	99	$	(21)	$	-
	held for the six months ended June 30, 2012

(a) Other, net activity consists of realized and unrealized gains (losses) included in income for the NDT funds held by Generation.

Commonwealth Edison Co [Member]

Fair Value Tables [Line Items]

Fair value of financial liabilities recorded at the carrying amount

	June 30, 2013
	Carrying		Fair Value
	Amount		Level 1		Level 2		Level 3		Total
Short-term liabilities	$	374	$	0	$	374	$	0	$	374
Long-term debt (including amounts due within one year)		5,451		0		6,033		18		6,051
Long-term debt to financing trust		206		0		0		210		210

	December 31, 2012
	Carrying		Fair Value
	Amount		Level 1		Level 2		Level 3		Total
Long-term debt (including amounts due within one year)	$	5,567	$	0	$	6,530	$	18	$	6,548
Long-term debt to financing trust		206		0		0		212		212

Assets and liabilities measured and recorded at fair value on recurring basis

As of June 30, 2013		Level 1		Level 2		Level 3		Total
Assets
Cash equivalents		$	70	$	0	$	0	$	70
Rabbi trust investments
Mutual funds(a)			6		0		0		6
	Rabbi trust investments subtotal		6		0		0		6

Total assets		$	76	$	0	$	0	$	76

Liabilities
Deferred compensation obligation			0		(8)		0		(8)
Mark-to-market derivative liabilities(b)			0		0		(85)		(85)

Total liabilities			0		(8)		(85)		(93)

Total net assets (liabilities)		$	76	$	(8)	$	(85)	$	(17)

As of December 31, 2012		Level 1		Level 2		Level 3		Total
Assets
Cash equivalents		$	111	$	0	$	0	$	111
Rabbi trust investments
Mutual funds(a)			8		0		0		8
	Rabbi trust investments subtotal		8		0		0		8

Total assets		$	119	$	0	$	0	$	119

Liabilities
Deferred compensation obligation			0		(8)		0		(8)
Mark-to-market derivative liabilities(b)(c)			0		0		(293)		(293)

Total liabilities			0		(8)		(293)		(301)

Total net assets (liabilities)		$	119	$	(8)	$	(293)	$	(182)

(a) The mutual funds held by the Rabbi trusts are classified as Level 1 as they are valued based upon quoted prices (unadjusted) in active markets.

(b) The Level 3 balance includes the current and noncurrent liability of $16 million and $69 million at June 30, 2013, respectively, and $18 million and $49 million at December 31, 2012, respectively, related to floating-to-fixed energy swap contracts with unaffiliated suppliers.

(c) The Level 3 balance includes the current liability of $226 million at December 31, 2012, related to the fair value of ComEd's financial swap contract with Generation which eliminated upon consolidation in Exelon's Consolidated Financial Statements.

Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis

Three Months Ended June 30, 2013	Mark-to-Market Derivatives
Balance as of March 31, 2013	$	(160)
Total realized / unrealized gains included in regulatory assets(a)(b)		75
Balance as of June 30, 2013	$	(85)

Six Months Ended June 30, 2013	Mark-to-Market Derivatives
Balance as of December 31, 2012	$	(293)
Total realized / unrealized gains included in regulatory assets(a)(b)		208
Balance as of June 30, 2013	$	(85)

(a) Includes $3 million of increases in fair value and $11 million of decreases in fair value and realized gains due to settlements of $82 million and $215 million associated with ComEd's financial swap contract with Generation for the three and six months ended June 30, 2013, respectively. All items eliminate upon consolidation in Exelon's Consolidated Financial Statements.

(b) Includes $9 million and $20 million of increases in the fair value and realized losses due to settlements of $1 million and $4 million recorded in purchased power expense associated with floating-to-fixed energy swap contracts with unaffiliated suppliers for the three and six months ended June 30, 2013, respectively.

Three Months Ended June 30, 2012	Mark-to-Market Derivatives
Balance as of March 31, 2012	$	(823)
Total realized / unrealized gains included in regulatory assets(a)(b)		206
Balance as of June 30, 2012	$	(617)

Six Months Ended June 30, 2012	Mark-to-Market Derivatives
Balance as of December 31, 2011	$	(800)
Total realized / unrealized gains included in regulatory assets(a)(b)		183
Balance as of June 30, 2012	$	(617)

Total realized and unrealized gains (losses) included in income for Level 3 assets and liabilities measured at fair value on a recurring basis

Includes $14 million of increases in fair value and $121 million of decreases in fair value and realized gains due to settlements of $161 million and $308 million of associated with ComEd's financial swap contract with Generation for the three and six months ended June 30, 2012, respectively. All items eliminate upon consolidation in Exelon's Consolidated Financial Statements.
Includes $30 million of decreases in fair value and $5 million of increases in fair value of floating-to-fixed energy swap contracts with unaffiliated suppliers for the three and six months ended June 30, 2012, respectively.

PECO Energy Co [Member]

Fair Value Tables [Line Items]

Fair value of financial liabilities recorded at the carrying amount

	June 30, 2013
	Carrying		Fair Value
	Amount		Level 1		Level 2		Level 3		Total
Short-term liabilities	$	210	$	0	$	210	$	0	$	210
Long-term debt (including amounts due within one year)		1,948		0		2,122		0		2,122
Long-term debt to financing trusts		184		0		0		182		182

	December 31, 2012
	Carrying		Fair Value
	Amount		Level 1		Level 2		Level 3		Total
Short-term liabilities	$	210	$	0	$	210	$	0	$	210
Long-term debt (including amounts due within one year)		1,947		0		2,264		0		2,264
Long-term debt to financing trusts		184		0		0		188		188
Preferred securities		87		0		82		0		82

Assets and liabilities measured and recorded at fair value on recurring basis

As of June 30, 2013	Level 1		Level 2		Level 3		Total
Assets
Cash equivalents	$	13	$	0	$	0	$	13
Rabbi trust investments
Mutual funds(a)(b)		9		0		0		9
Rabbi trust investments subtotal		9		0		0		9

Total assets		22		0		0		22

Liabilities
Deferred compensation obligation		0		(16)		0		(16)

Total liabilities		0		(16)		0		(16)

Total net assets (liabilities)	$	22	$	(16)	$	0	$	6

As of December 31, 2012	Level 1		Level 2		Level 3		Total
Assets
Cash equivalents	$	346	$	0	$	0	$	346
Rabbi trust investments
Mutual funds(a)(b)		9		0		0		9
Rabbi trust investments subtotal		9		0		0		9

Total assets		355		0		0		355

Liabilities
Deferred compensation obligation		0		(18)		0		(18)

Total liabilities		0		(18)		0		(18)

Total net assets (liabilities)	$	355	$	(18)	$	0	$	337

(a) The mutual funds held by the Rabbi trusts are classified as Level 1 as they are valued based upon quoted prices (unadjusted) in active markets.

(b) Excludes $14 million and $13 million of the cash surrender value of life insurance investments at June 30, 2013 and December 31, 2012, respectively.

Baltimore Gas and Electric Company [Member]

Fair Value Tables [Line Items]

Fair value of financial liabilities recorded at the carrying amount

	June 30, 2013
	Carrying		Fair Value
	Amount		Level 1			Level 2	Level 3		Total
Short-term liabilities	$	3	$	3	$	0	$	0	$	3
Long-term debt (including amounts due within one year)		2,444		0		2,598		0		2,598
Long-term debt to financing trusts		258		0		0		257		257

	December 31, 2012
	Carrying		Fair Value
	Amount		Level 1			Level 2	Level 3		Total
Long-term debt (including amounts due within one year)	$	2,178	$	0	$	2,468	$	0	$	2,468
Long-term debt to financing trusts		258		0		0		263		263

Assets and liabilities measured and recorded at fair value on recurring basis

As of June 30, 2013		Level 1		Level 2		Level 3		Total
Assets
Cash equivalents		$	365	$	0	$	0	$	365
Rabbi trust investments
	Mutual funds(a)		5		0		0		5
	Rabbi trust investments subtotal		5		0		0		5

Total assets			370		0		0		370

Liabilities
Deferred compensation obligation			0		(5)		0		(5)

Total liabilities			0		(5)		0		(5)

Total net assets (liabilities)		$	370	$	(5)	$	0	$	365

As of December 31, 2012		Level 1		Level 2		Level 3		Total
Assets
Cash equivalents		$	33	$	0	$	0	$	33
Rabbi trust investments
	Mutual funds(a)		5		0		0		5
	Rabbi trust investments subtotal		5		0		0		5

Total assets			38		0		0		38

Liabilities
Deferred compensation obligation			0		(5)		0		(5)

Total liabilities			0		(5)		0		(5)

Total net assets (liabilities)		$	38	$	(5)	$	0	$	33

- Definition

Tabular disclosure of the amount of gains or losses for the period included in earnings or resulted in a change to net assets, have arisen from the use of significant unobservable inputs (level 3) to measure the fair value of assets, liabilities, and financial instruments classified in shareholders' equity.

+ References+ Details

- Definition

Tabular disclosure of the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments, assets, and liabilities. Such certain disclosures about the financial instruments, assets, and liabilities include: (1) the fair value of the required items together with their carrying amounts (as appropriate) and (2) the methodology and assumptions used in developing such estimates of fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 107

-Paragraph 15

-Subparagraph b-d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 159

-Paragraph 18

-Subparagraph c(2), d, e, f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph a, c(1), c(2), c(3), d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13433-108611

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13467-108611

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

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+ Details