Fair Value of Financial Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Fair value of financial liabilities recorded at the carrying amount

		December 31, 2013								December 31, 2012
		Carrying		Fair Value						Carrying		Fair
		Amount			Level 1		Level 2		Level 3	Amount		Value
Short-term liabilities		$	344	$	3	$	341	$	0	$	214	$	214
Long-term debt (including amounts
	due within one year)		19,132		0		18,672		1,079		18,745		20,520
Long-term debt to financing trusts			648		0		0		631		648		664
SNF obligation			1,021		0		790		0		1,020		763
Preferred securities of subsidiary			0		0		0		0		87		82

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

As of December 31, 2013	Level 1		Level 2		Level 3		Total
Assets
Cash equivalents^(a)	$	1,230	$	0	$	0	$	1,230
Nuclear decommissioning trust fund investments
Cash equivalents		459		0		0		459
Equity
Individually held		1,776		0		0		1,776
Exchange traded funds		115		0		0		115
Commingled funds		0		2,271		0		2,271
Equity funds subtotal		1,891		2,271		0		4,162
Fixed income
Debt securities issued by the U.S. Treasury and other
U.S. government corporations and agencies		882		0		0		882
Debt securities issued by states of the United States
and political subdivisions of the states		0		294		0		294
Debt securities issued by foreign governments		0		87		0		87
Corporate debt securities		0		1,753		31		1,784
Federal agency mortgage-backed securities		0		10		0		10
Commercial mortgage-backed securities (non-agency)		0		40		0		40
Residential mortgage-backed securities (non-agency)		0		7		0		7
Mutual funds		0		18		0		18
Fixed income subtotal		882		2,209		31		3,122
Middle market lending		0		0		314		314
Private Equity		0		0		5		5
Other debt obligations		0		14		0		14
Nuclear decommissioning trust fund investments subtotal^(b)		3,232		4,494		350		8,076

Pledged assets for Zion decommissioning
Cash equivalents		0		26		0		26
Equity
Individually held		16		0		0		16
Equity funds subtotal		16		0		0		16
Fixed income
Debt securities issued by the U.S. Treasury and other
U.S. government corporations and agencies		45		4		0		49
Debt securities issued by states of the United States
and political subdivisions of the states		0		20		0		20
Corporate debt securities		0		227		0		227
Fixed income subtotal		45		251		0		296
Middle market lending		0		0		112		112
Other debt obligations		0		1		0		1
Pledged assets for Zion decommissioning subtotal^(c)		61		278		112		451

Rabbi trust investments
Cash equivalents		2		0		0		2
Mutual funds^(d)(e)		54		0		0		54
Rabbi trust investments subtotal		56		0		0		56

Commodity mark-to-market derivative assets
Economic hedges		493		2,582		885		3,960
Proprietary trading		324		1,315		122		1,761
Effect of netting and allocation of collateral^(f)		(863)		(3,131)		(430)		(4,424)
Commodity mark-to-market assets subtotal		(46)		766		577		1,297

Interest rate mark-to-market derivative assets		30		39		0		69
Effect of netting and allocation of collateral		(30)		(2)		0		(32)
Interest rate mark-to-market derivative assets subtotal		0		37		0		37

Other Investments		0		0		15		15

Total assets		4,533		5,575		1,054		11,162

Liabilities
Commodity mark-to-market derivative liabilities
Economic hedges		(540)		(1,890)		(590)		(3,020)
Proprietary trading		(328)		(1,256)		(119)		(1,703)
Effect of netting and allocation of collateral^(f)		869		3,007		404		4,280
Commodity mark-to-market liabilities subtotal^(h)		1		(139)		(305)		(443)

Interest rate mark-to-market derivative liabilities		(31)		(17)		0		(48)
Effect of netting and allocation of collateral		31		1		0		32
Interest rate mark-to-market derivative liabilities subtotal		0		(16)		0		(16)

Deferred compensation obligation		0		(114)		0		(114)

Total liabilities		1		(269)		(305)		(573)

Total net assets	$	4,534	$	5,306	$	749	$	10,589

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 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
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^(g)(h)		(83)		(228)		(289)		(600)
Interest rate mark-to-market 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 (liabilities) of $(5) million and $30 million at December 31, 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 assets of $7 million at both December 31, 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 $53 million related to deferred compensation and $1 million related to Supplemental Executive Retirement Plan at December 31, 2013, and $53 million related to deferred compensation and $16 million related to Supplemental Executive Retirement Plan at December 31, 2012.

(e) Excludes $32 million and $28 million of the cash surrender value of life insurance investments at December 31, 2013 and December 31, 2012, respectively.

(f) Includes collateral postings (received) from counterparties. Collateral (received) from counterparties, net of collateral paid to counterparties, totaled $6 million, $(124) million and $(26) million allocated to Level 1, Level 2 and Level 3 mark-to-market derivatives, respectively, as of December 31, 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 $17 million and $176 million at December 31, 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

For the Year Ended December 31, 2013		Nuclear Decommissioning Trust Fund Investment		Pledged Assets for Zion Station Decommissioning			Mark-to-Market Derivatives		Other Investments		Total
Balance as of January 1, 2013		$	183	$	89	$	367		$	17	$	656
Total realized / unrealized gains (losses)
	Included in net income		2		0		(44)	^(a)		0		(42)
	Included in other comprehensive income		0		0		0			2		2
	Included in regulatory assets		8		0		(126)	^(b)		0		(118)
Change in collateral			0		0		7			0		7
Purchases, sales, issuances and settlements
	Purchases		203		62		28			4		297
	Sales		(28)		(39)		(11)			(8)		(86)
	Settlements		(18)		-							(18)
Transfers into Level 3			0		0		86	^(c)		1		87
Transfers out of Level 3			0		0		(35)			(1)		(36)

Balance as of December 31, 2013		$	350	$	112	$	272		$	15	$	749
The amount of total gains included in income
	attributed to the change in unrealized gains related to assets and liabilities held as of December 31, 2013	$	1	$	0	$	167		$	0	$	168

(a) Includes a reduction for the reclassification of $211 million of realized gains due to settlement of derivative contracts recorded in results of operations for the year ended December 31, 2013.

(b) Excludes decreases in fair value of $11 million of and realized losses reclassified due to settlements of $215 million associated with Generation's financial swap contract with ComEd for the year ended December 31, 2013. All items eliminate upon consolidation in Exelon's Consolidated Financial Statements.

(c) Includes an increase of transfers into Level 3 arising from reductions in market liquidity, which resulted in less observable contract tenures in various locations.

(a) Includes a reduction for the reclassification of $155 million of realized gains due to the settlement of derivative contracts recorded in results of operations for the year ended December 31, 2012.

(b) Excludes $98 million of increases in fair value and $566 million of realized losses due to settlements for the year ended December 31, 2012 of Generation's financial swap contract with ComEd, which eliminates upon consolidation in Exelon's Consolidated Financial Statements. This position was de-designated as a cash flow hedge prior to the merger date.

(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


		Operating Revenue		Purchased Power and Fuel		Other, net ^(a)
Total gains (losses) included in income for the year ended
	December 31, 2013	$	(152)	$	108	$	2
Change in the unrealized gains relating to assets and liabilities
	held for the year ended December 31, 2013	$	40	$	127	$	1

		Operating Revenue		Purchased Power and Fuel		Other, net
Total gains included in income for the year ended
	December 31, 2012	$	54	$	5	$	0
Change in the unrealized gains (losses) relating to assets and liabilities
	held for the year ended December 31, 2012	$	230	$	(16)	$	0

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 December 31, 2013 ^(c)		Valuation Technique	Unobservable Input	Range
Mark-to-market derivatives – Economic Hedges (Generation) ^(a)	$	488	Discounted Cash Flow	Forward power price	$	8		-	$	176	(d)
			Discounted Cash Flow	Forward gas price	$	2.98		-	$	16.63	(d)
			Option Model	Volatility percentage		15	%	-		142	%

Mark-to-market derivatives – Proprietary trading (Generation) ^(a)	$	3	Discounted Cash Flow	Forward power price	$	10		-	$	176	(d)
			Option Model	Volatility percentage		14	%	-		19	%

Mark-to-market derivatives (ComEd)	$	(193)	Discounted Cash Flow	Forward heat rate ^(b)		8		-		9
				Marketability reserve		3.5	%	-		8	%
				Renewable factor		84	%	-		128	%

_____________________

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 that ended in May 2013, 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 3 positions of $33 million as of December 31, 2012.

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	%

Exelon Generation Co L L C [Member]

Fair Value Tables [Line Items]

Fair value of financial liabilities recorded at the carrying amount

		December 31, 2013								December 31, 2012
		Carrying		Fair Value						Carrying		Fair
		Amount			Level 1		Level 2		Level 3	Amount		Value
Short-term liabilities		$	22	$	0	$	22	$	0	$	0	$	0
Long-term debt (including amounts
	due within one year)		7,729		0		6,586		1,062		7,483		7,849
SNF obligation			1,021		0		790		0		1,020		763

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

As of December 31, 2013	Level 1		Level 2		Level 3			Total
Assets
Cash equivalents	$	1,006	$	0	$	0	$	1,006
Nuclear decommissioning trust fund investments
Cash equivalents		459		0		0		459
Equity
Individually held		1,776		0		0		1,776
Exchange traded funds		115		0		0		115
Commingled funds		0		2,271		0		2,271
Equity funds subtotal		1,891		2,271		0		4,162
Fixed income
Debt securities issued by the U.S. Treasury and other U.S.
government corporations and agencies		882		0		0		882
Debt securities issued by states of the United States and
political subdivisions of the states		0		294		0		294
Debt securities issued by foreign governments		0		87		0		87
Corporate debt securities		0		1,753		31		1,784
Federal agency mortgage-backed securities		0		10		0		10
Commercial mortgage-backed securities (non-agency)		0		40		0		40
Residential mortgage-backed securities (non-agency)		0		7		0		7
Mutual funds		0		18		0		18
Fixed income subtotal		882		2,209		31		3,122
Middle market lending		0		0		314		314
Private Equity		0		0		5		5
Other debt obligations		0		14		0		14
Nuclear decommissioning trust fund investments subtotal^(b)		3,232		4,494		350		8,076

Pledged assets for Zion Station decommissioning
Cash equivalents		0		26		0		26
Equity
Individually held		16		0		0		16
Equity funds subtotal		16		0		0		16
Fixed income
Debt securities issued by the U.S. Treasury and other U.S.
government corporations and agencies		45		4		0		49
Debt securities issued by states of the United States and
political subdivisions of the states		0		20		0		20
Corporate debt securities		0		227		0		227
Fixed income subtotal		45		251		0		296
Middle market lending		0		0		112		112
Other debt obligations		0		1		0		1
Pledged assets for Zion Station decommissioning subtotal^(c)		61		278		112		451

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

Commodity mark-to-market derivative assets
Economic hedges		493		2,582		885		3,960
Proprietary trading		324		1,315		122		1,761
Effect of netting and allocation of collateral^(e)		(863)		(3,131)		(430)		(4,424)
Commodity mark-to-market assets subtotal		(46)		766		577		1,297

Interest Rate mark-to-market derivative assets		30		32		0		62
Effect of netting and allocation of collateral		(30)		(2)		0		(32)
Interest Rate mark-to-market derivative assets subtotal		0		30		0		30

Other investments		0		0		15		15

Total assets		4,266		5,568		1,054		10,888

Liabilities
Commodity mark-to-market derivative liabilities
Economic hedges		(540)		(1,890)		(397)		(2,827)
Proprietary trading		(328)		(1,256)		(119)		(1,703)
Effect of netting and allocation of collateral^(e)		869		3,007		404		4,280
Commodity mark-to-market liabilities subtotal		1		(139)		(112)		(250)

Interest rate mark-to-market derivative liabilities		(31)		(13)		0		(44)
Effect of netting and allocation of collateral		31		1		0		32
Interest rate mark-to-market derivative liabilities subtotal		0		(12)		0		(12)

Deferred compensation obligation		0		(29)		0		(29)

Total liabilities		1		(180)		(112)		(291)

Total net assets	$	4,267	$	5,388	$	942	$	10,597

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)		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		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 subtotal		0		(33)		0	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 assets of $7 million at both December 31, 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) Excludes $10 million and $8 million of the cash surrender value of life insurance investments at December 31, 2013 and December 31, 2012, respectively.

(e) Includes collateral postings (received) from counterparties. Collateral (received) from counterparties, net of collateral paid to counterparties, totaled $6 million, $(124) million and $(26) million allocated to Level 1, Level 2 and Level 3 mark-to-market derivatives, respectively, as of December 31, 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.

(f) 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

For the Year Ended December 31, 2013		Nuclear Decommissioning Trust Fund Investments		Pledged Assets for Zion Station Decommissioning		Mark-to-Market Derivatives				Other Investments	Total
Balance as of January 1, 2013		$	183	$	89	$	660		$	17	$	949
Total unrealized / realized gains (losses)
	Included in income		2		0		(51)	^(a)(b)		0		(49)
	Included in other comprehensive income		0		0		(219)	^(b)		2		(217)
	Included in noncurrent payables to affiliates		8		0		0			0		8
Change in collateral			0		0		7			0		7
Purchases, sales, issuances and settlements
	Purchases		203		62		28			4		297
	Sales		(28)		(39)		(11)			(8)		(86)
	Settlements		(18)		0		0			0		(18)
Transfers into Level 3			0		0		86	^(c)		1		87
Transfers out of Level 3			0		0		(35)			(1)		(36)
Balance as of December 31, 2013		$	350	$	112	$	465		$	15	$	942
The amount of total losses included in income
	attributed to the change in unrealized gains related to assets and liabilities held as of December 31, 2013	$	1	$	0	$	156		$	0	$	157

(a) Includes a reduction for the reclassification of $207 million of realized gains due to the settlement of derivative contracts recorded in results of operations for the year ended December 31, 2013.

(b) Includes $11 million of increases in fair value and realized losses due to settlements of $215 million associated with Generation's financial swap contract with ComEd for the year ended December 31, 2013. All items eliminate upon consolidation in Exelon's Consolidated Financial Statements.

(c) Includes an increase of transfers into Level 3 arising from reductions in market liquidity, which resulted in less observable contract tenures in various locations.

For the Year Ended December 31, 2012		Nuclear Decommissioning Trust Fund Investments		Pledged Assets for Zion Station Decommissioning		Mark-to-Market Derivatives			Other Investments		Total
Balance as of January 1, 2012		$	13	$	37	$	817		$	0	$	867
Total realized / unrealized gains (losses)
	Included in income		0		0		66	^(a)		0		66
	Included in other comprehensive income		0		0		(475)	^(b)		0		(475)
	Included in noncurrent payables to affiliates		1		0		0			0		1
Changes in collateral			0		0		(32)			0		(32)
Purchases, sales, issuances and settlements
	Purchases		169		63		334	^(c)		17		583
	Sales		0		(11)		0			0		(11)
Transfers into Level 3			0		0		39			0		39
Transfers out of Level 3			0		0		(89)			0		(89)

Balance as of December 31, 2012		$	183	$	89	$	660			17	$	949

The amount of total gains included in income
	attributed to the change in unrealized gains related to assets and liabilities as of December 31, 2012	$	0	$	0	$	165		$	0	$	165

(a) Includes a reduction for the reclassification of $99 million of realized gains due to the settlement of derivative contracts recorded in results of operations for the year ended December 31, 2012.

(b) Includes $98 million of increases in fair value and $566 million of realized losses reclassified from OCI due to settlements associated with Generation's financial swap contract with ComEd for the year ended December 31, 2012. This position was de-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

		Operating Revenue		Purchased Power and Fuel		Other - net (a)
Total gains (losses) included in income for the year ended
	December 31, 2013	$	(158)	$	107	$	2
Change in the unrealized gains relating to assets and
	liabilities held for the year ended December 31, 2013	$	30	$	126	$	1

		Operating Revenue		Purchased Power and Fuel		Other - net (a)
Total gains included in income for the year ended
	December 31, 2012	$	61	$	5	$	0
Change in the unrealized gains (losses) relating to assets and
	liabilities held for the year ended December 31, 2012	$	181	$	(16)	$	0

Commonwealth Edison Co [Member]

Fair Value Tables [Line Items]

Fair value of financial liabilities recorded at the carrying amount

		December 31, 2013								December 31, 2012
		Carrying		Fair Value						Carrying		Fair
		Amount			Level 1		Level 2		Level 3	Amount		Value
Short-term liabilities		$	184	$	0	$	184	$	0	$	0	$	0
Long-term debt (including amounts
	due within one year)		5,675		0		6,238		17		5,567		6,548
Long-term debt to financing trust			206		0		0		202		206		212

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

As of December 31, 2013		Level 1		Level 2		Level 3		Total
Assets
Rabbi trust investments
Mutual funds			5		0		0		5
	Rabbi trust investments subtotal		5		0		0		5

Total assets			5		0		0		5

Liabilities
Deferred compensation obligation			0		(8)		0		(8)
Mark-to-market derivative liabilities^(b)			0		0		(193)		(193)

Total liabilities			0		(8)		(193)		(201)

Total net assets (liabilities)		$	5	$	(8)	$	(193)	$	(196)

As of December 31, 2012		Level 1		Level 2		Level 3		Total
Assets
Cash equivalents		$	111	$	0	$	0	$	111
Rabbi trust investments
Mutual funds			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^(a)(b)			0		0		(293)		(293)

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

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

(a) 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 eliminates upon consolidation in Exelon's Consolidated Financial Statements.

(b) The Level 3 balance includes the current and noncurrent liability of $17 million and $176 million at December 31, 2013, respectively, and $18 million and $49 million at December 31, 2012, respectively, related to floating-to-fixed energy swap contracts with unaffiliated suppliers.

Includes $98 million of increases in fair value and $566 million of realized gains due to settlements associated with ComEd's financial swap contract with Generation for the year ended December 31, 2012. All items eliminate upon consolidation in Exelon's Consolidated Financial Statements.
Includes $34 million of decreases in the fair value and realized losses due to settlements of $5 million recorded in purchased power expense associated with floating-to-fixed energy swap contracts with unaffiliated suppliers for the year ended December 31, 2012 .

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

For the Year Ended December 31, 2013	Mark-to-Market Derivatives
Balance as of January 1, 2013	$	(293)
Total realized / unrealized gains included in regulatory assets^(a)(b)		100
Balance as of December 31, 2013	$	(193)

(a) Includes $11 million of decrease in fair value and realized gains due to settlements of $215 million associated with ComEd's financial swap contract with Generation for the year ended December 31, 2013. All items eliminate upon consolidation in Exelon's Consolidated Financial Statements.

(b) Includes $126 million of increases in the fair value and realized losses due to settlements of $7 million recorded in purchased power expense associated with floating-to-fixed energy swap contracts with unaffiliated suppliers for the year ended December 31, 2013 .

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

Twelve Months Ended December 31, 2012	Mark-to-Market Derivatives
Balance as of January 1, 2012	$	(800)
Total realized / unrealized gains included in regulatory assets (a)(b)		507
Balance as of December 31, 2012	$	(293)

PECO Energy Co [Member]

Fair Value Tables [Line Items]

Fair value of financial liabilities recorded at the carrying amount

		December 31, 2013								December 31, 2012
		Carrying		Fair Value						Carrying		Fair
		Amount			Level 1		Level 2		Level 3	Amount		Value
Short-term liabilities		$	0	$	0	$	0	$	0	$	210	$	210
Long-term debt (including amounts
	due within one year)		2,197		0		2,358		0		1,947		2,264
Long-term debt to financing trusts			184		0		0		180		184		188
Preferred securities			0		0		0		0		87		82

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

As of December 31, 2013			Level 1		Level 2		Level 3		Total
Assets
Cash equivalents			$	175	$	0	$	0	$	175
Rabbi trust investments
	Mutual funds ^(a)			9		0		0		9

		Rabbi trust investments subtotal		9		0		0		9

Total assets				184		0		0		184

Liabilities
Deferred compensation obligation				0		(17)		0		(17)

Total liabilities				0		(17)		0		(17)

Total net assets (liabilities)			$	184	$	(17)	$	0	$	167

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

Baltimore Gas and Electric Company [Member]

Fair Value Tables [Line Items]

Fair value of financial liabilities recorded at the carrying amount

		December 31, 2013								December 31, 2012
		Carrying		Fair Value						Carrying		Fair
		Amount			Level 1		Level 2		Level 3	Amount		Value
Short-term liabilities		$	138	$	3	$	135	$	0	$	0	$	0
Long-term debt (including amounts
	due within one year)		2,011		0		2,148		0		2,178		2,468
Long-term debt to financing trusts			258		0		0		249		258		263

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

As of December 31, 2013			Level 1		Level 2		Level 3		Total
Assets
Cash equivalents			$	31	$	0	$	0	$	31
Rabbi trust investments
	Mutual funds			6		0		0		6

		Rabbi trust investments subtotal		6		0		0		6

Total assets				37		0		0		37

Liabilities
Deferred compensation obligation				0		(6)		0		(6)

Total liabilities				0		(6)		0		(6)

Total net assets (liabilities)			$	37	$	(6)	$	0	$	31

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

		Rabbit 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 fair value of financial instruments, including financial assets and financial liabilities, and the measurements of those instruments, assets, and liabilities.

+ References+ Details