Exelon (EXC) 10-K 5 Feb 10 2009 FY Annual report Financial data

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income (USD $)
In Millions, except Per Share data	12 Months Ended Dec. 31, 2009	12 Months Ended Dec. 31, 2008	12 Months Ended Dec. 31, 2007
EXELON CORP
Operating revenues
Total operating revenues	$17,318	$18,859	$18,916
Operating expenses
Purchased power	3,215	4,270	5,282
Fuel	2,066	2,312	2,360
Operating and maintenance	4,612	4,538	4,289
Operating and maintenance for regulatory required programs	63	28	0
Depreciation and amortization	1,834	1,634	1,520
Taxes other than income	778	778	797
Total operating expenses	12,568	13,560	14,248
Operating income	4,750	5,299	4,668
Other income and deductions
Interest expense	(654)	(699)	(647)
Interest expense to affiliates, net	(77)	(133)	(203)
Equity in earnings (losses) of investments	(27)	(26)	(106)
Other, net	426	(407)	460
Total other income and deductions	(332)	(1,265)	(496)
Income before income taxes	4,418	4,034	4,172
Income taxes	1,712	1,317	1,446
Income from continuing operations	2,706	2,717	2,726
Discontinued operations
Income (loss) from discontinued operations (net of taxes of $0, $1 and $3, respectively)	1	(1)	6
Gain on disposal of discontinued operations (net of taxes)	0	21	4
Income from discontinued operations, net	1	20	10
Net income	2,707	2,737	2,736
Average shares of common stock outstanding:
Basic	659	658	670
Diluted	662	662	676
Earnings per average common share-basic:
Income from continuing operations	4.1	4.13	4.06
Income from discontinued operations	$0	0.03	0.02
Net income	4.1	4.16	4.08
Earnings per average common share-diluted:
Income from continuing operations	4.09	4.1	4.03
Income from discontinued operations	$0	0.03	0.02
Net income	4.09	4.13	4.05
Dividends per common share	2.1	2.03	1.76
EXELON CORP | Retained Earnings
Discontinued operations
Net income	2,707	2,737	2,736
EXELON GENERATION CO LLC
Operating revenues
Operating revenues	6,231	7,168	7,211
Operating revenues from affiliates	3,472	3,586	3,538
Total operating revenues	9,703	10,754	10,749
Operating expenses
Purchased power	1,338	1,867	2,705
Fuel	1,594	1,705	1,746
Operating and maintenance	2,632	2,432	2,190
Operating and maintenance from affiliate	306	285	264
Depreciation and amortization	333	274	267
Taxes other than income	205	197	185
Total operating expenses	6,408	6,760	7,357
Operating income	3,295	3,994	3,392
Other income and deductions
Interest expense	(113)	(136)	(161)
Equity in earnings (losses) of investments	(3)	(1)	1
Other, net	376	(469)	155
Total other income and deductions	260	(606)	(5)
Income before income taxes	3,555	3,388	3,387
Income taxes	1,433	1,130	1,362
Income from continuing operations	2,122	2,258	2,025
Discontinued operations
Gain on disposal of discontinued operations (net of taxes)	0	20	4
Income from discontinued operations, net	0	20	4
Net income	2,122	2,278	2,029
EXELON GENERATION CO LLC | Retained Earnings
Discontinued operations
Net income	2,122	2,278	2,029
COMMONWEALTH EDISON CO
Operating revenues
Operating revenues	5,772	6,129	6,099
Operating revenues from affiliates	2	7	5
Total operating revenues	5,774	6,136	6,104
Operating expenses
Purchased power	1,609	2,077	2,270
Purchased power from affiliate	1,456	1,505	1,477
Operating and maintenance	863	929	895
Operating and maintenance for regulatory required programs	63	28	0
Operating and maintenance from affiliate	165	168	196
Depreciation and amortization	494	464	440
Taxes other than income	281	298	314
Total operating expenses	4,931	5,469	5,592
Operating income	843	667	512
Other income and deductions
Interest expense	(306)	(327)	(265)
Interest expense to affiliates, net	(13)	(21)	(53)
Equity in earnings (losses) of investments	0	(8)	(7)
Other, net	79	18	58
Total other income and deductions	(240)	(338)	(267)
Income before income taxes	603	329	245
Income taxes	229	128	80
Discontinued operations
Net income	374	201	165
COMMONWEALTH EDISON CO | Retained (Deficit) Earnings Unappropriated
Discontinued operations
Net income	374	201	165
PECO ENERGY CO
Operating revenues
Operating revenues	5,302	5,553	5,596
Operating revenues from affiliates	9	14	17
Total operating revenues	5,311	5,567	5,613
Operating expenses
Purchased power	269	328	307
Purchased power from affiliate	2,005	2,083	2,059
Fuel	472	607	617
Operating and maintenance	545	641	513
Operating and maintenance from affiliate	95	90	117
Depreciation and amortization	952	854	773
Taxes other than income	276	265	280
Total operating expenses	4,614	4,868	4,666
Operating income	697	699	947
Other income and deductions
Interest expense	(124)	(112)	(94)
Interest expense to affiliates, net	(63)	(114)	(154)
Equity in earnings (losses) of investments	(24)	(16)	(7)
Other, net	13	18	45
Total other income and deductions	(198)	(224)	(210)
Income before income taxes	499	475	737
Income taxes	146	150	230
Discontinued operations
Net income	353	325	507
Earnings per average common share-diluted:
Preferred security dividends	4	4	4
Net income on common stock	349	321	503
PECO ENERGY CO | Retained Earnings
Discontinued operations
Net income	$353	$325	$507

1_Consolidated Statements of Op

Consolidated Statements of Operations and Comprehensive Income (Parenthetical) (USD $)
In Millions	12 Months Ended Dec. 31, 2009	12 Months Ended Dec. 31, 2008	12 Months Ended Dec. 31, 2007
EXELON CORP
Income (loss) from discontinued operations, taxes	$0	$1	$3
Gain on disposal of discontinued operations, taxes	0	14	2
EXELON GENERATION CO LLC
Gain on disposal of discontinued operations, taxes	$0	$15	$2

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (USD $)
In Millions	12 Months Ended Dec. 31, 2009	12 Months Ended Dec. 31, 2008	12 Months Ended Dec. 31, 2007
EXELON CORP
Cash flows from operating activities
Net income	$2,707	$2,737	$2,736
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization and accretion	2,601	2,308	2,183
Impairment of long-lived assets	223	0	0
Deferred income taxes and amortization of investment tax credits	756	374	(104)
Net fair value changes related to derivatives	(95)	(515)	102
Net realized and unrealized (gains) losses on nuclear decommissioning trust fund investments	(207)	363	(70)
Other non-cash operating activities	652	870	734
Changes in assets and liabilities:
Accounts receivable	234	67	(585)
Inventories	51	(109)	9
Accounts payable, accrued expenses and other current liabilities	(254)	(44)	146
Option premiums (paid) received, net	(40)	(124)	27
Counterparty collateral received (posted), net	196	1,027	(516)
Income taxes	(29)	(38)	160
Pension and non-pension postretirement benefit contributions	(588)	(230)	(204)
Other assets and liabilities	(113)	(135)	(122)
Net cash flows provided by operating activities	6,094	6,551	4,496
Cash flows from investing activities
Capital expenditures	(3,273)	(3,117)	(2,674)
Proceeds from nuclear decommissioning trust fund sales	22,905	17,202	7,312
Investment in nuclear decommissioning trust funds	(23,144)	(17,487)	(7,527)
Proceeds from sales of investments	41	0	95
Purchases of investments	(28)	0	0
Change in restricted cash	35	29	(45)
Other investing activities	6	(5)	(70)
Net cash flows used in investing activities	(3,458)	(3,378)	(2,909)
Cash flows from financing activities
Changes in short-term debt	(56)	(405)	311
Issuance of long-term debt	1,987	2,265	1,621
Retirement of long-term debt	(1,773)	(1,398)	(262)
Retirement of long-term debt to financing affiliates	(709)	(1,038)	(1,020)
Dividends paid on common stock	(1,385)	(1,335)	(1,180)
Proceeds from employee stock plans	42	130	215
Purchase of treasury stock	0	(436)	(1,208)
Purchase of forward contract in relation to certain treasury stock	0	(64)	(79)
Other financing activities	(3)	68	102
Net cash flows (used in) provided by financing activities	(1,897)	(2,213)	(1,500)
Increase (decrease) in cash and cash equivalents	739	960	87
Cash and cash equivalents at beginning of period	1,271	311	224
Cash and cash equivalents at end of period	2,010	1,271	311
EXELON CORP | Retained Earnings
Cash flows from operating activities
Net income	2,707	2,737	2,736
EXELON GENERATION CO LLC
Cash flows from operating activities
Net income	2,122	2,278	2,029
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization and accretion	1,098	947	928
Impairment of long-lived assets	223	0	0
Deferred income taxes and amortization of investment tax credits	671	327	(31)
Net fair value changes related to derivatives	(95)	(515)	139
Net realized and unrealized (gains) losses on nuclear decommissioning trust fund investments	(207)	363	(70)
Other non-cash operating activities	104	332	256
Changes in assets and liabilities:
Accounts receivable	172	79	(204)
Receivables from and payables to affiliates, net	(54)	(51)	288
Inventories	(29)	(60)	(38)
Accounts payable, accrued expenses and other current liabilities	(43)	(91)	(22)
Option premiums (paid) received, net	(40)	(124)	27
Counterparty collateral received (posted), net	195	1,029	(518)
Income taxes	79	115	269
Pension and non-pension postretirement benefit contributions	(265)	(103)	(99)
Other assets and liabilities	(1)	(81)	40
Net cash flows provided by operating activities	3,930	4,445	2,994
Cash flows from investing activities
Capital expenditures	(1,977)	(1,699)	(1,269)
Proceeds from nuclear decommissioning trust fund sales	22,905	17,202	7,312
Investment in nuclear decommissioning trust funds	(23,144)	(17,487)	(7,527)
Proceeds from sales of investments	0	0	95
Changes in Exelon intercompany money pool	0	0	13
Change in restricted cash	17	25	(45)
Other investing activities	(21)	(8)	(3)
Net cash flows used in investing activities	(2,220)	(1,967)	(1,424)
Cash flows from financing activities
Issuance of long-term debt	1,546	0	746
Retirement of long-term debt	(1,065)	(13)	(11)
Distribution to member	(2,276)	(1,545)	(2,357)
Contribution from member	57	86	54
Other financing activities	(8)	2	(3)
Net cash flows (used in) provided by financing activities	(1,746)	(1,470)	(1,571)
Increase (decrease) in cash and cash equivalents	(36)	1,008	(1)
Cash and cash equivalents at beginning of period	1,135	127	128
Cash and cash equivalents at end of period	1,099	1,135	127
EXELON GENERATION CO LLC | Retained Earnings
Cash flows from operating activities
Net income	2,122	2,278	2,029
COMMONWEALTH EDISON CO
Cash flows from operating activities
Net income	374	201	165
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization and accretion	495	465	441
Deferred income taxes and amortization of investment tax credits	265	258	82
Other non-cash operating activities	309	264	206
Changes in assets and liabilities:
Accounts receivable	29	(133)	(103)
Receivables from and payables to affiliates, net	(27)	112	(132)
Inventories	4	(4)	6
Accounts payable, accrued expenses and other current liabilities	(48)	43	120
Income taxes	(105)	(95)	(93)
Pension and non-pension postretirement benefit contributions	(214)	(55)	(53)
Other assets and liabilities	(62)	23	(119)
Net cash flows provided by operating activities	1,020	1,079	520
Cash flows from investing activities
Capital expenditures	(854)	(953)	(1,040)
Proceeds from sales of investments	41	0	0
Purchases of investments	(28)	0	0
Other investing activities	20	(5)	25
Net cash flows used in investing activities	(821)	(958)	(1,015)
Cash flows from financing activities
Changes in short-term debt	95	(310)	310
Issuance of long-term debt	191	1,324	705
Retirement of long-term debt	(208)	(760)	(147)
Retirement of long-term debt to financing affiliates	0	(429)	(349)
Contributions from parent	8	14	28
Dividends paid on common stock	(240)	0	0
Other financing activities	(1)	0	0
Net cash flows (used in) provided by financing activities	(155)	(161)	547
Increase (decrease) in cash and cash equivalents	44	(40)	52
Cash and cash equivalents at beginning of period	47	87	35
Cash and cash equivalents at end of period	91	47	87
COMMONWEALTH EDISON CO | Retained (Deficit) Earnings Unappropriated
Cash flows from operating activities
Net income	374	201	165
PECO ENERGY CO
Cash flows from operating activities
Net income	353	325	507
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization and accretion	952	854	773
Deferred income taxes and amortization of investment tax credits	(210)	(220)	(186)
Other non-cash operating activities	141	194	86
Changes in assets and liabilities:
Accounts receivable	36	(120)	(158)
Receivables from and payables to affiliates, net	45	(1)	(58)
Inventories	76	(45)	40
Accounts payable, accrued expenses and other current liabilities	(123)	46	78
Income taxes	(18)	(12)	(51)
Pension and non-pension postretirement benefit contributions	(52)	(38)	(31)
Other assets and liabilities	(34)	(14)	(20)
Net cash flows provided by operating activities	1,166	969	980
Cash flows from investing activities
Capital expenditures	(388)	(392)	(339)
Change in restricted cash	1	1	1
Other investing activities	10	14	1
Net cash flows used in investing activities	(377)	(377)	(337)
Cash flows from financing activities
Changes in short-term debt	(95)	(151)	151
Issuance of long-term debt	250	941	172
Retirement of long-term debt	0	(604)	(17)
Retirement of long-term debt to financing affiliates	(709)	(609)	(671)
Changes in Exelon intercompany money pool	0	0	(45)
Repayment of receivable from parent	320	284	306
Contributions from parent	27	36	32
Dividends paid on common stock	(312)	(480)	(562)
Dividends paid on preferred securities	(4)	(4)	(4)
Other financing activities	(2)	0	0
Net cash flows (used in) provided by financing activities	(525)	(587)	(638)
Increase (decrease) in cash and cash equivalents	264	5	5
Cash and cash equivalents at beginning of period	39	34	29
Cash and cash equivalents at end of period	303	39	34
PECO ENERGY CO | Retained Earnings
Cash flows from operating activities
Net income	$353	$325	$507

Consolidated Balance Sheets

Consolidated Balance Sheets (USD $)
In Millions	Dec. 31, 2009	Dec. 31, 2008
EXELON CORP
Current assets
Cash and cash equivalents	$2,010	$1,271
Restricted cash and investments	40	75
Accounts receivable, net
Customer	1,563	1,928
Other	486	324
Mark-to-market derivative assets	376	480
Inventories, net
Fossil fuel	198	315
Materials and supplies	559	528
Other	209	209
Total current assets	5,441	5,130
Property, plant and equipment, net	27,341	25,813
Deferred debits and other assets
Regulatory assets	4,872	5,940
Nuclear decommissioning trust funds	6,669	5,500
Investments	704	670
Investments in affiliates	20	45
Goodwill	2,625	2,625
Mark-to-market derivative assets	649	679
Other	859	1,144
Total deferred debits and other assets	16,398	16,603
Total assets	49,180	47,546
Current liabilities
Short-term borrowings	155	211
Long-term debt due within one year	639	29
Long-term debt to PECO Energy Transition Trust due within one year	415	319
Accounts payable	1,345	1,416
Mark-to-market derivative liabilities	198	212
Accrued expenses	923	1,151
Deferred income taxes	152	77
Other	411	396
Total current liabilities	4,238	3,811
Long-term debt	10,995	11,397
Long-term debt to PECO Energy Transition Trust	0	805
Long-term debt to financing trust	390	390
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits	5,750	4,939
Asset retirement obligations	3,434	3,734
Pension obligations	3,625	4,111
Non-pension postretirement benefit obligations	2,180	2,255
Spent nuclear fuel obligation	1,017	1,015
Regulatory liabilities	3,492	2,520
Mark-to-market derivative liabilities	23	23
Other	1,309	1,412
Total deferred credits and other liabilities	20,830	20,009
Total liabilities	36,453	36,412
Commitments and contingencies
Preferred securities	87	87
Shareholders' equity
Common stock	8,923	8,816
Treasury stock, at cost (35 and 35 shares held at December 31, 2009 and December 31, 2008, respectively)	(2,328)	(2,338)
Retained earnings	8,134	6,820
Accumulated other comprehensive income (loss), net	(2,089)	(2,251)
Total shareholders' equity	12,640	11,047
Total liabilities and shareholders' equity	49,180	47,546
EXELON CORP | Common Stock
Shareholders' equity
Total shareholders' equity	8,923	8,816
EXELON CORP | Treasury Stock
Shareholders' equity
Total shareholders' equity	(2,328)	(2,338)
EXELON CORP | Retained Earnings
Shareholders' equity
Total shareholders' equity	8,134	6,820
EXELON CORP | Accumulated Other Comprehensive (Loss) Income
Shareholders' equity
Total shareholders' equity	(2,089)	(2,251)
EXELON GENERATION CO LLC
Current assets
Cash and cash equivalents	1,099	1,135
Restricted cash	5	22
Accounts receivable, net
Customer	495	673
Other	112	108
Mark-to-market derivative assets	376	480
Mark-to-market derivative assets with affiliate	302	111
Receivables from affiliates	297	277
Inventories, net
Fossil fuel	102	143
Materials and supplies	470	435
Other	102	102
Total current assets	3,360	3,486
Property, plant and equipment, net	9,809	8,907
Deferred debits and other assets
Nuclear decommissioning trust funds	6,669	5,500
Investments	46	33
Receivable from affiliate	1	1
Mark-to-market derivative assets	639	662
Mark-to-market derivative assets with affiliate	671	345
Prepaid pension asset	1,027	949
Other	184	201
Total deferred debits and other assets	9,237	7,691
Total assets	22,406	20,084
Current liabilities
Long-term debt due within one year	26	12
Accounts payable	826	792
Mark-to-market derivative liabilities	198	212
Accrued expenses	670	761
Payables to affiliates	80	78
Deferred income taxes	399	256
Other	63	57
Total current liabilities	2,262	2,168
Long-term debt	2,967	2,502
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits	2,707	1,968
Asset retirement obligations	3,316	3,536
Pension obligations	0	63
Non-pension postretirement benefit obligations	659	576
Spent nuclear fuel obligation	1,017	1,015
Payables to affiliates	2,228	1,336
Mark-to-market derivative liabilities	21	23
Other	437	331
Total deferred credits and other liabilities	10,385	8,848
Total liabilities	15,614	13,518
Member's equity
Membership interest	3,464	3,407
Undistributed earnings	2,169	2,323
Accumulated other comprehensive income, net	1,157	835
Total member's equity	6,790	6,565
Noncontrolling interest	2	1
Total equity	6,792	6,566
Total liabilities and equity	22,406	20,084
EXELON GENERATION CO LLC | Retained Earnings
Member's equity
Total equity	2,169	2,323
EXELON GENERATION CO LLC | Accumulated Other Comprehensive (Loss) Income
Member's equity
Total equity	1,157	835
EXELON GENERATION CO LLC | Membership Interest
Member's equity
Total equity	3,464	3,407
EXELON GENERATION CO LLC | Noncontrolling Interest
Member's equity
Total equity	2	1
COMMONWEALTH EDISON CO
Current assets
Cash and cash equivalents	91	47
Restricted cash	2	1
Accounts receivable, net
Customer	676	798
Other	318	162
Inventories, net
Inventories, net	71	75
Regulatory assets	358	169
Deferred income taxes	39	32
Other	24	25
Total current assets	1,579	1,309
Property, plant and equipment, net	12,125	11,655
Deferred debits and other assets
Regulatory assets	1,096	858
Investments	28	34
Goodwill	2,625	2,625
Receivable from affiliate	1,920	1,291
Prepaid pension asset	907	847
Other	417	618
Total deferred debits and other assets	6,993	6,273
Total assets	20,697	19,237
Current liabilities
Short-term borrowings	155	60
Long-term debt due within one year	213	17
Accounts payable	274	307
Accrued expenses	282	306
Payables to affiliates	177	179
Customer deposits	131	119
Mark-to-market derivative liability with affiliate	302	111
Other	63	54
Total current liabilities	1,597	1,153
Long-term debt	4,498	4,709
Long-term debt to financing trust	206	206
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits	2,648	2,369
Asset retirement obligations	95	174
Non-pension postretirement benefit obligations	241	203
Regulatory liabilities	3,145	2,440
Mark-to-market derivative liabilities with affiliate	669	345
Other	716	903
Total deferred credits and other liabilities	7,514	6,434
Total liabilities	13,815	12,502
Shareholders' equity
Common stock	1,588	1,588
Other paid-in capital	4,990	4,982
Retained earnings	304	170
Accumulated other comprehensive income (loss), net	0	(5)
Total shareholders' equity	6,882	6,735
Total liabilities and shareholders' equity	20,697	19,237
COMMONWEALTH EDISON CO | Common Stock
Shareholders' equity
Total shareholders' equity	1,588	1,588
COMMONWEALTH EDISON CO | Accumulated Other Comprehensive (Loss) Income
Shareholders' equity
Total shareholders' equity	0	(5)
COMMONWEALTH EDISON CO | Other Paid-In Capital
Shareholders' equity
Total shareholders' equity	4,990	4,982
COMMONWEALTH EDISON CO | Retained (Deficit) Earnings Unappropriated
Shareholders' equity
Total shareholders' equity	(1,639)	(1,639)
COMMONWEALTH EDISON CO | Retained Earnings Appropriated
Shareholders' equity
Total shareholders' equity	1,943	1,809
PECO ENERGY CO
Current assets
Cash and cash equivalents	303	39
Restricted cash	1	2
Accounts receivable, net
Customer	392	457
Other	120	39
Inventories, net
Fossil fuel	96	172
Materials and supplies	18	18
Deferred income taxes	65	78
Other	11	14
Total current assets	1,006	819
Property, plant and equipment, net	5,297	5,074
Deferred debits and other assets
Regulatory assets	1,834	2,597
Investments	18	15
Investments in affiliates	13	39
Receivable from affiliate	311	47
Other	540	578
Total deferred debits and other assets	2,716	3,276
Total assets	9,019	9,169
Current liabilities
Short-term borrowings	0	95
Long-term debt to PECO Energy Transition Trust due within one year	415	319
Accounts payable	164	204
Accrued expenses	74	120
Payables to affiliates	189	144
Customer deposits	65	74
Other	32	25
Total current liabilities	939	981
Long-term debt	2,221	1,971
Long-term debt to PECO Energy Transition Trust	0	805
Long-term debt to financing trust	184	184
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits	2,241	2,451
Asset retirement obligations	24	24
Non-pension postretirement benefit obligations	296	283
Regulatory liabilities	317	49
Mark-to-market derivative liabilities	2	0
Mark-to-market derivative liabilities with affiliate	2	0
Other	141	152
Total deferred credits and other liabilities	3,023	2,959
Total liabilities	6,367	6,900
Commitments and contingencies
Preferred securities	87	87
Shareholders' equity
Common stock	2,318	2,291
Receivable from parent	(180)	(500)
Retained earnings	426	389
Accumulated other comprehensive income (loss), net	1	2
Total shareholders' equity	2,565	2,182
Total liabilities and shareholders' equity	9,019	9,169
PECO ENERGY CO | Common Stock
Shareholders' equity
Total shareholders' equity	2,318	2,291
PECO ENERGY CO | Retained Earnings
Shareholders' equity
Total shareholders' equity	426	389
PECO ENERGY CO | Accumulated Other Comprehensive (Loss) Income
Shareholders' equity
Total shareholders' equity	1	2
PECO ENERGY CO | Receivable from Parent
Shareholders' equity
Total shareholders' equity	($180)	($500)

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) (EXELON CORP, USD $)
Share data in Millions	Dec. 31, 2009	Dec. 31, 2008
Common stock, par value	$0	$0
Common stock, shares authorized	2,000	2,000
Common stock, shares outstanding	660	658
Treasury stock, shares held	35	35

Consolidated Statement of Chang

Consolidated Statement of Changes in Equity (USD $)
In Millions, except Share data in Thousands	12 Months Ended Dec. 31, 2009	12 Months Ended Dec. 31, 2008	12 Months Ended Dec. 31, 2007	Dec. 31, 2006
EXELON CORP
Beginning Balance	$11,047	$10,137	$10,007
Net income	2,707	2,737	2,736
Long-term incentive plan activity	112	217	328
Employee stock purchase plan issuances		19	16
Common stock purchases		(499)	(1,287)
Common stock dividends	(1,388)	(1,007)	(1,219)
Adoption of the fair value option for financial assets and liabilities, net of income taxes		0
Adoption of accounting for uncertain tax positions			(13)
Other comprehensive (loss) income, net of income taxes	162	(557)	(431)
Ending Balance	12,640	11,047	10,137	10,007
EXELON CORP | Common Stock
Beginning Balance (in shares)	692,953	689,183	682,474
Beginning Balance	8,816	8,579	8,314
Long-term incentive plan activity (in shares)	1,612	3,452	6,455
Long-term incentive plan activity	107	217	328
Employee stock purchase plan issuances (in shares)		318	254
Employee stock purchase plan issuances		19	16
Common stock purchases		1	(79)
Ending Balance (in shares)	694,565	692,953	689,183	682,474
Ending Balance	8,923	8,816	8,579	8,314
EXELON CORP | Treasury Stock
Beginning Balance	(2,338)	(1,838)	(630)
Long-term incentive plan activity	10
Common stock purchases		(500)	(1,208)
Ending Balance	(2,328)	(2,338)	(1,838)	(630)
EXELON CORP | Retained Earnings
Beginning Balance	6,820	4,930	3,426
Net income	2,707	2,737	2,736
Long-term incentive plan activity	(5)
Common stock dividends	(1,388)	(1,007)	(1,219)
Adoption of the fair value option for financial assets and liabilities, net of income taxes		160
Adoption of accounting for uncertain tax positions			(13)
Ending Balance	8,134	6,820	4,930	3,426
EXELON CORP | Accumulated Other Comprehensive (Loss) Income
Beginning Balance	(2,251)	(1,534)	(1,103)
Adoption of the fair value option for financial assets and liabilities, net of income taxes		(160)
Other comprehensive (loss) income, net of income taxes	162	(557)	(431)
Ending Balance	(2,089)	(2,251)	(1,534)	(1,103)
EXELON GENERATION CO LLC
Beginning Balance	6,566	4,370	5,484
Net income	2,122	2,278	2,029
Adjustment of the adoption of accounting for uncertain tax positions		1
Distribution to member	(2,276)	(1,545)	(2,357)
Allocation of tax benefit from member	57	86	54
Adoption of the fair value option for financial assets and liabilities, net of income taxes		0
Adoption of accounting for uncertain tax positions			(43)
Transfer of AmerGen pension and non-pension postretirement benefit plans to Exelon, net of income taxes	20
Other comprehensive (loss) income, net of income taxes	302	1,376	(797)
Noncontrolling interest in income of consolidated entity	1
Ending Balance	6,792	6,566	4,370	5,484
EXELON GENERATION CO LLC | Retained Earnings
Beginning Balance	2,323	1,429	1,800
Net income	2,122	2,278	2,029
Adjustment of the adoption of accounting for uncertain tax positions		1
Distribution to member	(2,276)	(1,545)	(2,357)
Adoption of the fair value option for financial assets and liabilities, net of income taxes		160
Adoption of accounting for uncertain tax positions			(43)
Ending Balance	2,169	2,323	1,429	1,800
EXELON GENERATION CO LLC | Accumulated Other Comprehensive (Loss) Income
Beginning Balance	835	(381)	416
Adoption of the fair value option for financial assets and liabilities, net of income taxes		(160)
Transfer of AmerGen pension and non-pension postretirement benefit plans to Exelon, net of income taxes	20
Other comprehensive (loss) income, net of income taxes	302	1,376	(797)
Ending Balance	1,157	835	(381)	416
EXELON GENERATION CO LLC | Membership Interest
Beginning Balance	3,407	3,321	3,267
Allocation of tax benefit from member	57	86	54
Ending Balance	3,464	3,407	3,321	3,267
EXELON GENERATION CO LLC | Noncontrolling Interest
Beginning Balance	1	1	1
Noncontrolling interest in income of consolidated entity	1
Ending Balance	2	1	1	1
COMMONWEALTH EDISON CO
Beginning Balance	6,735	6,528	6,298
Net income	374	201	165
Allocation of tax benefit from parent	8	14	28
Appropriation of retained earnings for future dividends	0	0	0
Adjustment of the adoption of accounting for uncertain tax positions		(2)
Common stock dividends	(240)
Adoption of accounting for uncertain tax positions			33
Other comprehensive (loss) income, net of income taxes	5	(6)	4
Ending Balance	6,882	6,735	6,528	6,298
COMMONWEALTH EDISON CO | Common Stock
Beginning Balance	1,588	1,588	1,588
Ending Balance	1,588	1,588	1,588	1,588
COMMONWEALTH EDISON CO | Accumulated Other Comprehensive (Loss) Income
Beginning Balance	(5)	1	(3)
Other comprehensive (loss) income, net of income taxes	5	(6)	4
Ending Balance	0	(5)	1	(3)
COMMONWEALTH EDISON CO | Other Paid-In Capital
Beginning Balance	4,982	4,968	4,906
Allocation of tax benefit from parent	8	14	28
Adoption of accounting for uncertain tax positions			34
Ending Balance	4,990	4,982	4,968	4,906
COMMONWEALTH EDISON CO | Retained (Deficit) Earnings Unappropriated
Beginning Balance	(1,639)	(1,639)	(1,632)
Net income	374	201	165
Appropriation of retained earnings for future dividends	(374)	(199)	(171)
Adjustment of the adoption of accounting for uncertain tax positions		(2)
Adoption of accounting for uncertain tax positions			(1)
Ending Balance	(1,639)	(1,639)	(1,639)	(1,632)
COMMONWEALTH EDISON CO | Retained Earnings Appropriated
Beginning Balance	1,809	1,610	1,439
Appropriation of retained earnings for future dividends	374	199	171
Common stock dividends	(240)
Ending Balance	1,943	1,809	1,610	1,439
PECO ENERGY CO
Beginning Balance	2,182	2,023	1,722
Net income	353	325	507
Preferred security dividends	(4)	(4)	(4)
Allocation of tax benefit from parent	27	36	32
Repayment of receivable from parent	320	284	306
Common stock dividends	(312)	(480)	(562)
Adoption of accounting for uncertain tax positions			23
Other comprehensive (loss) income, net of income taxes	(1)	(2)	(1)
Ending Balance	2,565	2,182	2,023	1,722
PECO ENERGY CO | Common Stock
Beginning Balance	2,291	2,255	2,223
Allocation of tax benefit from parent	27	36	32
Ending Balance	2,318	2,291	2,255	2,223
PECO ENERGY CO | Retained Earnings
Beginning Balance	389	548	584
Net income	353	325	507
Preferred security dividends	(4)	(4)	(4)
Common stock dividends	(312)	(480)	(562)
Adoption of accounting for uncertain tax positions			23
Ending Balance	426	389	548	584
PECO ENERGY CO | Accumulated Other Comprehensive (Loss) Income
Beginning Balance	2	4	5
Other comprehensive (loss) income, net of income taxes	(1)	(2)	(1)
Ending Balance	1	2	4	5
PECO ENERGY CO | Receivable from Parent
Beginning Balance	(500)	(784)	(1,090)
Repayment of receivable from parent	320	284	306
Ending Balance	($180)	($500)	($784)	($1,090)

2_Consolidated Statement of Cha

Consolidated Statement of Changes in Equity (Parenthetical) (USD $)
In Millions	12 Months Ended Dec. 31, 2009	12 Months Ended Dec. 31, 2008	12 Months Ended Dec. 31, 2007
EXELON CORP
Adoption of the fair value option for financial assets and liabilities, income taxes		$286
Other comprehensive (loss) income, income taxes	119	(354)	(290)
EXELON GENERATION CO LLC
Adoption of the fair value option for financial assets and liabilities, income taxes		286
Other comprehensive (loss) income, income taxes	199	908	(524)
Transfer of AmerGen pension and non-pension postretirement benefit plans to Exelon, income taxes	17
COMMONWEALTH EDISON CO
Other comprehensive (loss) income, income taxes	3	(4)	3
PECO ENERGY CO
Other comprehensive (loss) income, income taxes	($1)	($1)	($1)

Statement Of Other Comprehensiv

Statement Of Other Comprehensive Income (USD $)
In Millions	12 Months Ended Dec. 31, 2009	12 Months Ended Dec. 31, 2008	12 Months Ended Dec. 31, 2007
EXELON CORP
Net income	$2,707	$2,737	$2,736
Pension and non-pension postretirement benefit plans:
Prior service benefit reclassified to periodic cost, net of income taxes	(13)	(9)	(9)
Actuarial loss reclassified to periodic cost, net of income taxes	93	60	74
Transition obligation reclassified to periodic cost, net of income taxes	3	3	3
Pension and non-pension postretirement benefit plan valuation adjustment, net of income taxes	86	(1,459)	19
Change in unrealized gain (loss) on cash flow hedges, net of income taxes	(12)	855	(513)
Change in unrealized gain (loss) on marketable securities, net of income taxes	5	(7)	(5)
Other comprehensive (loss) income	162	(557)	(431)
Comprehensive income	2,869	2,180	2,305
EXELON CORP | Retained Earnings
Net income	2,707	2,737	2,736
EXELON CORP | Accumulated Other Comprehensive (Loss) Income
Pension and non-pension postretirement benefit plans:
Other comprehensive (loss) income	162	(557)	(431)
EXELON GENERATION CO LLC
Net income	2,122	2,278	2,029
Pension and non-pension postretirement benefit plans:
Pension and non-pension postretirement benefit plan valuation adjustment, net of income taxes	0	(27)	5
Change in unrealized gain (loss) on cash flow hedges, net of income taxes	302	1,403	(795)
Change in unrealized gain (loss) on marketable securities, net of income taxes	0	0	(7)
Other comprehensive (loss) income	302	1,376	(797)
Comprehensive income	2,424	3,654	1,232
EXELON GENERATION CO LLC | Retained Earnings
Net income	2,122	2,278	2,029
EXELON GENERATION CO LLC | Accumulated Other Comprehensive (Loss) Income
Pension and non-pension postretirement benefit plans:
Other comprehensive (loss) income	302	1,376	(797)
COMMONWEALTH EDISON CO
Net income	374	201	165
Pension and non-pension postretirement benefit plans:
Change in unrealized gain (loss) on cash flow hedges, net of income taxes	0	0	4
Change in unrealized gain (loss) on marketable securities, net of income taxes	5	(6)	0
Other comprehensive (loss) income	5	(6)	4
Comprehensive income	379	195	169
COMMONWEALTH EDISON CO | Accumulated Other Comprehensive (Loss) Income
Pension and non-pension postretirement benefit plans:
Other comprehensive (loss) income	5	(6)	4
COMMONWEALTH EDISON CO | Retained (Deficit) Earnings Unappropriated
Net income	374	201	165
PECO ENERGY CO
Net income	353	325	507
Pension and non-pension postretirement benefit plans:
Amortization of realized loss on settled cash flow swaps, net of income taxes	(1)	(1)	(1)
Change in unrealized gain (loss) on marketable securities, net of income taxes	0	(1)	0
Other comprehensive (loss) income	(1)	(2)	(1)
Comprehensive income	352	323	506
PECO ENERGY CO | Retained Earnings
Net income	353	325	507
PECO ENERGY CO | Accumulated Other Comprehensive (Loss) Income
Pension and non-pension postretirement benefit plans:
Other comprehensive (loss) income	($1)	($2)	($1)

3_Statement Of Other Comprehens

Statement Of Other Comprehensive Income (Parenthetical) (USD $)
In Millions	12 Months Ended Dec. 31, 2009	12 Months Ended Dec. 31, 2008	12 Months Ended Dec. 31, 2007
EXELON CORP
Prior service benefit reclassified to periodic cost, taxes	($6)	($6)	($4)
Actuarial loss reclassified to periodic cost, taxes	74	52	57
Transition obligation reclassified to periodic cost, taxes	2	2	2
Pension and non-pension postretirement benefit plan valuation adjustment, taxes	47	(959)	1
Change in unrealized gain (loss) on cash flow hedges, taxes	(2)	563	(345)
Change in unrealized gain (loss) on marketable securities, taxes	3	(6)	(1)
EXELON GENERATION CO LLC
Pension and non-pension postretirement benefit plan valuation adjustment, taxes	0	(18)	3
Change in unrealized gain (loss) on cash flow hedges, taxes	199	926	(525)
Change in unrealized gain (loss) on marketable securities, taxes	0	0	(2)
COMMONWEALTH EDISON CO
Change in unrealized gain (loss) on cash flow hedges, taxes	0	0	2
Change in unrealized gain (loss) on marketable securities, taxes	3	(4)	1
PECO ENERGY CO
Change in unrealized gain (loss) on marketable securities, taxes	0	(1)	0
Amortization of realized loss on settled cash flow swaps, taxes	($1)	$0	($1)

Significant Accounting Policies

Significant Accounting Policies (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Significant Accounting Policies (Exelon, Generation, ComEd and PECO)	1. Significant Accounting Policies (Exelon, Generation, ComEd and PECO) Description of Business (Exelon, Generation, ComEd and PECO) Exelon is a utility services holding company engaged, through its subsidiaries, in the generation and energy delivery businesses discussed below. The generation business consists of the electric generating facilities, the wholesale energy marketing operations and competitive retail supply operations of Generation. The energy delivery businesses include the purchase and regulated retail sale of electricity and the provision of transmission and distribution services by ComEd in northern Illinois, including the City of Chicago, and by PECO in southeastern Pennsylvania, including the City of Philadelphia, and the purchase and regulated retail sale of natural gas and the provision of distribution services by PECO in the Pennsylvania counties surrounding the City of Philadelphia. Basis of Presentation (Exelon, Generation, ComEd and PECO) Through its business services subsidiary, BSC, Exelon provides its subsidiaries with a variety of support services at cost, including legal, human resources, financial, information technology and supply management services. The costs of BSC, including support services, are directly charged or allocated to the applicable subsidiaries using a cost-causative allocation method. Corporate governance type costs that cannot be directly assigned are allocated based on a Modified Massachusetts formula, which is a method that utilizes a combination of gross revenues, total assets and direct labor costs for the allocation base. The results of Exelons corporate operations are presented as Other within the consolidated financial statements and include intercompany eliminations unless otherwise disclosed. Exelon owns 100% of all of its significant consolidated subsidiaries, either directly or indirectly, except for ComEd, of which Exelon owns more than 99%, and PECO, of which Exelon owns 100% of the common stock but none of PECOs preferred securities. Exelon has reflected the third-party interests in ComEd, which totaled less than $1 million at December31, 2009 and December31, 2008 as equity and PECOs preferred securities as preferred securities of subsidiaries in its consolidated financial statements. Generation owns 100% of all of its significant consolidated subsidiaries, either directly or indirectly, except for Exelon SHC, Inc., of which Generation owns 99% and the remaining 1% is indirectly owned by Exelon, which is eliminated in Exelons consolidated financial statements. AmerGen, a wholly owned subsidiary of Generation through January8, 2009, owned and operated the Clinton, Three Mile Island (TMI) Unit No.1 and Oyster Creek generating stations. Effective January8, 2009, AmerGen was merged into Generation, and Generation now holds the operating licenses for Clinton, TMI and Oyster Creek and owns and operates those plants. Each of Generations, ComEds and PECOs consolidated financial statements includes the accounts of their subsidiaries. All intercompany transactions have been eliminated. Certain prior year amounts in Exelons, Generations and ComEds Consolidated

Regulatory Issues

Regulatory Issues (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Regulatory Issues (Exelon, Generation, ComEd and PECO)	2.Regulatory Issues (Exelon, Generation, ComEd and PECO) Illinois Settlement Agreement (Exelon, Generation and ComEd).In July 2007, following extensive discussions with legislative leaders in Illinois, ComEd, Generation and other utilities and generators in Illinois reached an agreement (Illinois Settlement) with various parties concluding discussions of measures to address concerns about higher electric bills in Illinois without rate freeze, generation tax or other legislation that Exelon believes would be harmful to consumers of electricity, electric utilities, generators of electricity and the State of Illinois. Legislation reflecting the Illinois Settlement (Illinois Settlement Legislation) was signed into law in August2007. The Illinois Settlement and the Illinois Settlement Legislation provide for the following, among other things: Rate Relief Programs Various Illinois electric utilities, their affiliates and generators of electricity in Illinois agreed to contribute approximately $1 billion over a period of four years (2007-2010) to programs to provide rate relief to Illinois electricity customers and funding for the IPA created by the Illinois Settlement Legislation. ComEd committed to issue $64 million in rate relief credits to customers or to fund various programs to assist customers. Generation committed to contribute an aggregate of $747 million, consisting of $435 million to pay ComEd for rate relief programs for ComEd customers, $307.5 million for rate relief programs for customers of other Illinois utilities and $4.5 million for partially funding operations of the IPA. The contributions are recognized in the financial statements of Generation and ComEd as rate relief credits are applied to customer bills by ComEd and other Illinois utilities or as operating expenses associated with the programs are incurred. During the years ended December31, 2009, 2008 and 2007, Generation and ComEd recognized net costs from their contributions pursuant to the Illinois Settlement in their Consolidated Statements of Operations as follows: Year Ended December31, 2009 Generation ComEd TotalCreditsIssued toComEdCustomers Credits to ComEd customers (a) $ 45 $ 8 $ 53 Credits to other Illinois utilities customers (a) 53 n/a n/a Other rate relief programs (b) 1 n/a Total incurred costs $ 98 $ 9 $ 53 Year Ended December31, 2008 Generation ComEd TotalCreditsIssued toComEdCustomers Credits to ComEd customers (a) $ 131 $ 6 $ 137 Credits to other Illinois utilities customers (a) 90 n/a n/a Other rate relief programs (b) 7 n/a Total incurred costs $ 221 $ 13 $ 137 Year Ended December31, 2007 Generation ComEd TotalCreditsIssued toComEdCustomers Credits to ComEd customers (a) $ 246 $ 33 $ 279 Credits to other Illinois utilities customers (a) 157 n/a n/a Other rate relief programs (b) 8 n/a Funding of the IPA (a)

Accounts Receivable

Accounts Receivable (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Accounts Receivable (Exelon, Generation, ComEd and PECO)	3. Accounts Receivable (Exelon, Generation, ComEd and PECO) Accounts receivable at December31, 2009 and 2008 included estimated unbilled revenues, representing an estimate for the unbilled amount of energy or services provided to customers, and is net of an allowance for uncollectible accounts as follows: 2009 Exelon Generation ComEd PECO Unbilled revenues $ 1,035 $ 441 $ 289 $ 305 Allowance for uncollectible accounts (225 ) (31 ) (77 ) (117 ) 2008 Exelon Generation ComEd PECO Unbilled revenues $ 1,199 $ 593 $ 310 $ 296 Allowance for uncollectible accounts (238 ) (30 ) (57 ) (151 ) PECO is party to an agreement with a financial institution under which it sold an undivided interest, adjusted daily, in up to $225 million of designated accounts receivable, which PECO accounted for as a sale as of December31, 2009. Under new guidance effective January1, 2010, this agreement will be accounted for as a secured borrowing. See Note 1Significant Accounting Policies for additional information. PECO retains the servicing responsibility for the sold receivables and has recorded a servicing liability. The agreement terminates on September16, 2010, unless extended in accordance with its terms. As of December31, 2009, PECO was in compliance with the requirements of the agreement. In the event the agreement is not extended, PECO has sufficient short-term liquidity and will seek alternate financing. See Note 7Fair Value of Financial Assets and Liabilities for additional information regarding the servicing liability.

Property, Plant and Equipment

Property, Plant and Equipment (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Property, Plant and Equipment (Exelon, Generation, ComEd and PECO)	4. Property, Plant and Equipment (Exelon, Generation, ComEd and PECO) Exelon The following table presents a summary of property, plant and equipment by asset category as of December31, 2009 and 2008: AverageServiceLife (years) 2009 2008 Asset Category Electrictransmission and distribution 5-75 $ 19,441 $ 18,509 Electricgeneration 1-72 9,666 9,108 Gastransportation and distribution 5-66 1,679 1,631 Commonelectric and gas 5-50 517 496 Nuclear fuel (a) 1-8 3,340 2,811 Construction work in progress N/A 1,263 1,038 Other property, plant and equipment (b) 5-58 458 462 Total property, plant and equipment 36,364 34,055 Less: accumulated depreciation (c) 9,023 8,242 Property, plant and equipment, net $ 27,341 $ 25,813 (a) Includes nuclear fuel that is in the fabrication and installation phase of $711 million and $490 million at December31, 2009 and 2008, respectively. (b) Includes Generations buildings under capital lease with a net carrying value of $28 million and $31 million at December31, 2009 and 2008, respectively. The original cost basis of the buildings was $53 million and total accumulated amortization was $24 million and $22 million as of December31, 2009 and 2008, respectively. Also includes unregulated property at ComEd and PECO. (c) Includes accumulated depreciation related to regulated property at ComEd and PECO of $4,565 million and $4,205 million as of December31, 2009 and 2008, respectively. Includes accumulated amortization of nuclear fuel in the reactor core at Generation of $1,383 million and $1,214 million as of December31, 2009 and 2008, respectively. On December2, 2009, Generation announced its intention to permanently retire four of its fossil-fired generating units effective May31, 2011. Exelon recorded approximately $32 million of additional depreciation expense to reflect changes in useful lives for the plant assets that will be taken out of service prior to their previously estimated service period. See Note 14Corporate Restructuring and Plant Retirements for additional information. The following table presents the annual depreciation provisions as a percentage of average service life for each asset category. Average Service Life Percentage by Asset Category 2009 2008 2007 Electrictransmission and distribution 2.43 % 2.42 % 2.38 % Electricgeneration 2.28 % 2.02 % 1.90 % Gas 1.75 % 1.74 % 1.69 % Commonelectric and gas 6.41 % 6.51 % 6.36 % Generation The following table presents a summary of property, plant and equipment by asset category as of December31, 2009 and 2008: AverageServiceLife (years) 2009 2008 Asset Category Electricgeneration 1-72 $ 9,666 $ 9,108 Nuclear fuel (a) 1-8 3,340 2,811 Construction work in progress N/A 964 744 Other property, plant and equipment (b) 5-58

Jointly Owned Electric Utility

Jointly Owned Electric Utility Plant (Exelon, Generation and PECO)
	12 Months Ended Dec. 31, 2009 USD / shares
EXELON CORP
Jointly Owned Electric Utility Plant (Exelon, Generation and PECO)	5. Jointly Owned Electric Utility Plant (Exelon, Generation and PECO) Exelons, Generations and PECOs undivided ownership interests in jointly owned electric plants at December31, 2009 and 2008 were as follows: Nuclear generation Fossil fuel generation Transmission Other Quad Cities Peach Bottom Salem(a) Keystone Conemaugh Wyman PA (b) DE/NJ (c) Other(d) Operator Generation Generation PSEG Nuclear Reliant Reliant FPL First Energy PSGE Ownership interest 75.00 % 50.00 % 42.59 % 20.99 % 20.72 % 5.89 % 22.00 % 42.55 % 44.24 % Exelons share at December31, 2009: Plant $ 570 $ 520 $ 386 $ 357 $ 236 $ 3 $ 5 $ 60 $ 1 Accumulated depreciation 101 263 79 119 151 2 4 28 Construction work in progress 107 56 46 1 11 Exelons share at December31, 2008: Plant $ 512 $ 490 $ 379 $ 192 $ 233 $ 2 $ 5 $ 60 $ 1 Accumulated depreciation 85 256 73 114 148 1 4 27 Construction work in progress 60 21 37 107 2 1 (a) Generation also owns a proportionate share in the fossil fuel combustion turbine at Salem, which is fully depreciated. The gross book value was $3 million at December31, 2009 and 2008. (b) PECO owns a 22.00% share in 127 miles of 500,000 voltage lines located in Pennsylvania. (c) PECO owns a 42.55% share in 131 miles of 500,000 voltage lines located in Delaware and New Jersey. (d) Generation has a 44.24% ownership interest in Merrill Creek Reservoir located in New Jersey. Exelons, Generations and PECOs undivided ownership interests are financed with their funds and all operations are accounted for as if such participating interests were wholly owned facilities. Exelons, Generations and PECOs share of direct expenses of the jointly owned plants are included in fuel and operating and maintenance expenses on Exelons and Generations Consolidated Statements of Operations and in operating and maintenance expenses on PECOs Consolidated Statements of Operations.
EXELON GENERATION CO LLC
Jointly Owned Electric Utility Plant (Exelon, Generation and PECO)	5. Jointly Owned Electric Utility Plant (Exelon, Generation and PECO) Exelons, Generations and PECOs undivided ownership interests in jointly owned electric plants at December31, 2009 and 2008 were as follows: Nuclear generation Fossil fuel generation Transmission Other Quad Cities Peach Bottom Salem(a) Keystone Conemaugh Wyman PA (b) DE/NJ (c) Other(d) Operator Generation Generation PSEG Nuclear Reliant Reliant FPL First Energy PSGE Ownership interest 75.00 % 50.00 % 42.59 % 20.99 % 20.72 % 5.89 % 22.00 % 42.55 % 44.24 % Exelons share at December31, 2009: Plant $ 570 $ 520 $ 386 $ 357 $ 236 $ 3 $ 5 $ 60 $ 1 Accumulated depreciation 101 263 79 119 151 2 4 28 Construction work in progress 107 56 46 1 11 Exelons share at December31, 2008: Plant $ 512 $ 490 $ 379 $ 192 $ 233 $ 2 $ 5 $ 60 $ 1 Accumulated depreciation 85 256 73 114 148 1 4 27 Construction work in progress 60 21 37 107 2 1 (a) Generation also owns a proportionate share in the fossil fuel combustion turbine at Salem, which is fully depreciated. The gross book value was $3 million at December31, 2009 and 2008. (b) PECO owns a 22.00% share in 127 miles of 500,000 voltage lines located in Pennsylvania. (c) PECO owns a 42.55% share in 131 miles of 500,000 voltage lines located in Delaware and New Jersey. (d) Generation has a 44.24% ownership interest in Merrill Creek Reservoir located in New Jersey. Exelons, Generations and PECOs undivided ownership interests are financed with their funds and all operations are accounted for as if such participating interests were wholly owned facilities. Exelons, Generations and PECOs share of direct expenses of the jointly owned plants are included in fuel and operating and maintenance expenses on Exelons and Generations Consolidated Statements of Operations and in operating and maintenance expenses on PECOs Consolidated Statements of Operations.
PECO ENERGY CO
Jointly Owned Electric Utility Plant (Exelon, Generation and PECO)	5. Jointly Owned Electric Utility Plant (Exelon, Generation and PECO) Exelons, Generations and PECOs undivided ownership interests in jointly owned electric plants at December31, 2009 and 2008 were as follows: Nuclear generation Fossil fuel generation Transmission Other Quad Cities Peach Bottom Salem(a) Keystone Conemaugh Wyman PA (b) DE/NJ (c) Other(d) Operator Generation Generation PSEG Nuclear Reliant Reliant FPL First Energy PSGE Ownership interest 75.00 % 50.00 % 42.59 % 20.99 % 20.72 % 5.89 % 22.00 % 42.55 % 44.24 % Exelons share at December31, 2009: Plant $ 570 $ 520 $ 386 $ 357 $ 236 $ 3 $ 5 $ 60 $ 1 Accumulated depreciation 101 263 79 119 151 2 4 28 Construction work in progress 107 56 46 1 11 Exelons share at December31, 2008: Plant $ 512 $ 490 $ 379 $ 192 $ 233 $ 2 $ 5 $ 60 $ 1 Accumulated depreciation 85 256 73 114 148 1 4 27 Construction work in progress 60 21 37 107 2 1 (a) Generation also owns a proportionate share in the fossil fuel combustion turbine at Salem, which is fully depreciated. The gross book value was $3 million at December31, 2009 and 2008. (b) PECO owns a 22.00% share in 127 miles of 500,000 voltage lines located in Pennsylvania. (c) PECO owns a 42.55% share in 131 miles of 500,000 voltage lines located in Delaware and New Jersey. (d) Generation has a 44.24% ownership interest in Merrill Creek Reservoir located in New Jersey. Exelons, Generations and PECOs undivided ownership interests are financed with their funds and all operations are accounted for as if such participating interests were wholly owned facilities. Exelons, Generations and PECOs share of direct expenses of the jointly owned plants are included in fuel and operating and maintenance expenses on Exelons and Generations Consolidated Statements of Operations and in operating and maintenance expenses on PECOs Consolidated Statements of Operations.

Intangible Assets

Intangible Assets (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Intangible Assets (Exelon, Generation, ComEd and PECO)	6.Intangible Assets (Exelon, Generation, ComEd and PECO) Goodwill Exelons and ComEds gross amount of goodwill, accumulated impairment losses and carrying amount of goodwill for the years ended December31, 2009 and 2008 were as follows: 2009 2008 Gross Amount(a) Accumulated Impairment Losses Carrying Amount Gross Amount(a) Accumulated Impairment Losses Carrying Amount Balance, January1 $ 4,608 $ 1,983 $ 2,625 $ 4,608 $ 1,983 $ 2,625 Impairment losses Balance, December31, $ 4,608 $ 1,983 $ 2,625 $ 4,608 $ 1,983 $ 2,625 (a) Reflects goodwill recorded in 2000 from the PECO/Unicom merger net of amortization, resolution of tax matters and other non-impairment-related changes as allowed under previous authoritative guidance. Goodwill is not amortized, but is subject to an assessment for impairment at least annually, or more frequently if events or circumstances indicate that goodwill might be impaired. The impairment assessment is performed using a two-step, fair value based test. The first step compares the fair value of the reporting unit to its carrying amount, including goodwill. If the carrying amount of the reporting unit exceeds its fair value, the second step is performed. The second step requires an allocation of fair value to the individual assets and liabilities using purchase price allocation in order to determine the implied fair value of goodwill. If the implied fair value of goodwill is less than the carrying amount, an impairment loss is recorded as a reduction to goodwill and a charge to operating expense. Exelon assesses goodwill impairment at its ComEd reporting unit. Accordingly, any goodwill impairment charge at ComEd will affect Exelons consolidated results of operations. As a result of new authoritative guidance for fair value measurement effective January1, 2009, Exelon and ComEd now estimate the fair value of the ComEd reporting unit using a weighted combination of a discounted cash flow analysis and a market multiples analysis instead of the expected cash flow approach used in 2008 and prior years. The discounted cash flow analysis relies on a single scenario reflecting base case orbest estimate projected cash flows for ComEds business and includes an estimate of ComEds terminal value based on these expected cash flows using the generally accepted Gordon Dividend Growth formula, which derives a valuation using an assumed perpetual annuity based on the entitys residual cash flows. The discount rate is based on the generally accepted Capital Asset Pricing Model and represents the weighted average cost of capital of comparable companies. The market multiples analysis utilizes multiples of business enterprise value to earnings, before interest, taxes, depreciation and amortization (EBITDA) of comparable companies in estimating fair value. Significant assumptions used in estimating the fair value include ComEds capital structure, discount and growth rates, utility sector market performance, operating and capi

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Fair Value of Financial Assets and Liabilities (Exelon, Generation, ComEd and PECO)	7. Fair Value of Financial Assets and Liabilities (Exelon, Generation, ComEd and PECO) Non-Derivative Financial Assets and Liabilities. As of December31, 2009 and 2008, the Registrants carrying amounts of cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities are representative of fair value because of the short-term nature of these instruments. Fair Value of Financial Liabilities Recorded at the Carrying Amount Exelon The carrying amounts and fair values of Exelons long-term debt and SNF obligation as of December31, 2009 and 2008 were as follows: 2009 2008 Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt (including amounts due within one year) $ 11,634 $ 12,223 $ 11,426 $ 10,803 Long-term debt to PETT (including amounts due within one year) 415 426 1,124 1,193 Long-term debt to other financing trusts 390 325 390 200 Spent nuclear fuel obligation 1,017 832 1,015 544 Preferred securities of subsidiary 87 63 87 63 Fair values of long-term debt are determined by a valuation model, which is based on a conventional discounted cash flow methodology and utilizes assumptions of current market pricing curves. The fair value of preferred securities of subsidiaries is determined using observable market prices as these securities are actively traded. The carrying amount of Exelons and Generations SNF obligation resulted from a contract with the DOE to provide for disposal of SNF from Generations nuclear generating stations. Exelons and Generations obligation to the DOE accrues at the 13-week Treasury rate and fair value was determined by comparing the carrying amount of the obligation at the 13-week Treasury rate to the present value of the obligation discounted using the prevailing Treasury rate for a long-term obligation with an estimated maturity of 2020 (after being adjusted for Generations credit risk). Generation The carrying amounts and fair values of Generations long-term debt and SNF obligation as of December31, 2009 and 2008 were as follows: 2009 2008 Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt (including amounts due within one year) $ 2,993 $ 3,132 $ 2,514 $ 2,402 Spent nuclear fuel obligation 1,017 832 1,015 544 ComEd The carrying amounts and fair values of ComEds long-term debt as of December31, 2009 and 2008 were as follows: 2009 2008 Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt (including amounts due within one year) $ 4,711 $ 5,062 $ 4,726 $ 4,510 Long-term debt to financing trust 206 167 206 100 PECO The carrying amounts and fair values of PECOs long-term debt and preferred securities as of December31, 2009 and 2008 were as follows: 2009 2008 Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt (including amounts due within one year)

Derivative Financial Instrument

Derivative Financial Instruments (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Derivative Financial Instruments (Exelon, Generation, ComEd and PECO)	8. Derivative Financial Instruments (Exelon, Generation, ComEd and PECO) The Registrants are exposed to certain risks related to ongoing business operations. The primary risks managed by using derivative instruments are commodity price risk and interest rate risk. To the extent the amount of energy Exelon generates differs from the amount of energy it has contracted to sell, the Registrants are exposed to market fluctuations in the prices of electricity, fossil fuels, and other commodities. The Registrants employ established policies and procedures to manage their risks associated with market fluctuations by entering into physical contracts as well as financial derivative contracts including swaps, futures, forwards, options and short-term and long-term commitments to purchase and sell energy and energy-related products. The Registrants believe these instruments, which are classified as either economic hedges or non-derivatives, mitigate exposure to fluctuations in commodity prices. Exposure to interest rate risk exists as a result of the issuance of variable and fixed-rate debt, commercial paper and lines of credit. Derivative accounting guidance requires that derivative instruments be recognized as either assets or liabilities at fair value. Under these provisions, economic hedges are recognized on the balance sheet at their fair value unless they qualify for the normal purchases and normal sales scope exception. The Registrants have applied the normal purchases and normal sales scope exception to certain derivative contracts for the forward sale of generation, power procurement agreements, and natural gas supply agreements. For economic hedges that qualify and are designated as cash flow hedges, the portion of the derivative gain or loss that is effective in offsetting the change in value of the underlying exposure is deferred in accumulated OCI and later reclassified into earnings when the underlying transaction occurs. For economic hedges that do not qualify or are not designated as cash flow hedges, changes in the fair value of the derivative are recognized in earnings each period and are classified as other derivatives in the following tables. Non-derivative contracts for access to additional generation and for sales to load-serving entities are accounted for primarily under the accrual method of accounting, which is further discussed in Note18 Commitments and Contingencies. Additionally, Generation is exposed to certain market risks through its proprietary trading activities. The proprietary activities are a complement to Generations energy marketing portfolio but represent a small portion of Generations overall energy marketing activities. Commodity Price Risk (Exelon, Generation, ComEd and PECO) Economic Hedging.The Registrants are exposed to commodity price risk primarily relating to changes in the market price of electricity, fossil fuels, and other commodities associated with price movements resulting from changes in supply and demand, fuel costs, market liquidity, weather conditions, governmental regulatory and environmental policies, and other factors. Within Exelon, Generation has the most exposure to commod

Debt and Credit Agreements

Debt and Credit Agreements (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Debt and Credit Agreements (Exelon, Generation, ComEd and PECO)	9. Debt and Credit Agreements (Exelon, Generation, ComEd and PECO) Short-Term Borrowings Exelon meets its short-term liquidity requirements primarily through the issuance of commercial paper. Generation and PECO meet their short-term liquidity requirements primarily through the issuance of commercial paper and borrowings from the intercompany money pool. ComEd meets its short-term liquidity requirements primarily through borrowings under its credit facility. Exelon, Generation, ComEd and PECO had the following amounts of commercial paper and credit facility borrowings outstanding at December31, 2009 and 2008: Commercial Paper Issuer MaximumProgram Size at December31, 2009 (a) MaximumProgram Size at December31, 2008 (a) Outstanding CommercialPaperat December31, 2009 Outstanding CommercialPaperat December31, 2008 Exelon Corporate $ 957 $ 957 $ $ 56 Generation 4,834 4,834 ComEd (b) 952 952 PECO 574 574 95 Total $ 7,317 $ 7,317 $ $ 151 (a) Equals aggregate bank commitments under revolving credit agreements. (b) Prior to July22, 2009, ComEd was unable to access the commercial paper market given the market environment. On July22, 2009, ComEds commercial paper rating was upgraded giving it limited access to the commercial paper market. However, ComEd did not issue commercial paper due to more favorable rates available to it on credit facility draws. Credit facility borrowings December31,2009 December31,2008 ComEd $ 155 $ 60 In order to maintain their respective commercial paper programs in the amounts indicated above, each Registrant must have revolving credit facilities in place, at least equal to the amount of its commercial paper program. While the amount of its commercial paper outstanding does not reduce available capacity under a Registrants credit agreement, each Registrant cannot issue commercial paper in an aggregate amount exceeding the available capacity under its credit agreement. The following tables present the short-term borrowings activity for Exelon, Generation, ComEd and PECO during 2009, 2008 and 2007: Exelon 2009 2008 2007 Average borrowings $ 132 $ 636 $ 500 Maximum borrowings outstanding 523 1,646 1,210 Average interest rates, computed on a daily basis 0.73 % 3.22 % 5.55 % Average interest rates, at December31 0.69 % 0.93 % 5.44 % Generation 2009 2008 2007 Average borrowings $ $ 340 $ 44 Maximum borrowings outstanding 1,211 740 Average interest rates, computed on a daily basis n.a. 3.13 % 5.51 % Average interest rates, at December31 n.a. n.a. n.a. ComEd 2009 2008 2007 Average borrowings $ 82 $ 140 $ 291 Maximum borrowings outstanding 265 568 605 Average interest rates, computed on a d

Income Taxes

Income Taxes (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Income Taxes (Exelon, Generation, ComEd and PECO)	10. Income Taxes (Exelon, Generation, ComEd and PECO) Income tax expense (benefit) from continuing operations is comprised of the following components: For the Year Ended December31, 2009 Exelon Generation ComEd PECO Included in operations: Federal Current $ 803 $ 631 $ (39 ) $ 329 Deferred 775 648 228 (143 ) Investment tax credit amortization (12 ) (7 ) (3 ) (2 ) State Current 154 131 4 26 Deferred (8 ) 30 39 (64 ) Total $ 1,712 $ 1,433 $ 229 $ 146 For the Year Ended December31, 2008 Exelon Generation ComEd PECO Included in operations: Federal Current $ 790 $ 669 $ (125 ) $ 327 Deferred 341 229 230 (147 ) Investment tax credit amortization (12 ) (7 ) (3 ) (2 ) State Current 169 150 (7 ) 43 Deferred 29 89 33 (71 ) Total $ 1,317 $ 1,130 $ 128 $ 150 For the Year Ended December31, 2007 Exelon Generation ComEd PECO Included in operations: Federal Current $ 1,269 $ 1,144 $ 2 $ 372 Deferred 34 (20 ) 65 (133 ) Investment tax credit amortization (12 ) (7 ) (3 ) (2 ) State Current 285 249 (3 ) 45 Deferred (130 ) (4 ) 19 (52 ) Total $ 1,446 $ 1,362 $ 80 $ 230 The effective income tax rate from continuing operations varies from the U.S. Federal statutory rate principally due to the following: For the Year Ended December31, 2009 Exelon Generation ComEd PECO U.S. Federal statutory rate 35.0 % 35.0 % 35.0 % 35.0 % Increase (decrease) due to: State income taxes, net of Federal income tax benefit 2.1 3.0 4.7 (5.0 ) Qualified nuclear decommissioning trust fund income 3.1 3.8 Domestic production activities deduction (0.9 ) (1.1 ) Tax exempt income (0.1 ) (0.2 ) Nontaxable postretirement benefits (0.2 ) (0.2 ) (0.5 ) (0.3 ) Amortization of investment tax credit (0.2 ) (0.1 ) (0.5 ) (0.4 ) Plant basis differences (0.3 ) (0.1 ) Other 0.1 (0.4 ) 0.1 Effective income tax rate 38.8 % 40.3 % 38.0 % 29.3 % For the Year Ended December31, 2008 Exelon Generation ComEd PECO U.S. Federal statutory rate 3

Asset Retirement Obligations

Asset Retirement Obligations (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Asset Retirement Obligations (Exelon, Generation, ComEd and PECO)	11. Asset Retirement Obligations (Exelon, Generation, ComEd and PECO) Nuclear Decommissioning Asset Retirement Obligations Generation has a legal obligation to decommission its nuclear power plants following the expiration of their operating licenses. Generation will pay for its respective obligations using trust funds that have been established for this purpose. The following table provides a rollforward of the nuclear decommissioning ARO reflected on Exelons and Generations Consolidated Balance Sheets, from January1, 2008 to December31, 2009: Exelon and Generation Nuclear decommissioning ARO at January1, 2008 $ 3,578 Net decrease resulting from updates to estimated future cash flows (300 ) Accretion expense 221 Payments to decommission retired plants (14 ) Nuclear decommissioning ARO at December31, 2008 (a) 3,485 Net decrease resulting from updates to estimated future cash flows (409 ) Accretion expense 203 Payments to decommission retired plants (19 ) Nuclear decommissioning ARO at December31, 2009 (a) $ 3,260 (a) Includes $17 million and $13 million as the current portion of the ARO at December31, 2009 and 2008, respectively, which is included in other current liabilities on Exelons and Generations Consolidated Balance Sheets. During 2009, Generation recorded a net decrease in the ARO of $409 million, primarily due to an update in the third quarter of 2009, which reflected updated decommissioning cost studies received for six nuclear units and a decline from the previous year in the cost escalation factor assumptions used to estimate future undiscounted decommissioning costs. This decrease in the ARO resulted in the recognition of $47 million of income (pre-tax), which is included in operating and maintenance expense in Exelons and Generations Consolidated Statements of Operations, representing the reduction in the ARO in excess of the existing ARC balances for the Non-Regulatory Agreement Units. During 2008, Generation recorded a net decrease in the ARO of $300 million, primarily due to an update in the third quarter of 2008, which reflected updated decommissioning cost studies received for seven nuclear units, a decline from the previous year in the cost escalation factor assumptions used to estimate future undiscounted decommissioning costs and a change in managements expectation of the year in which the DOE will begin accepting SNF (from the previous estimate of 2018 to 2020), partially offset by a change in the probabilities assigned to decommissioning alternatives for Zion Station to reflect a revised probability for accelerated decommissioning. The decrease in the ARO resulted in the recognition of $19 million of income (pre-tax), which is included in operating and maintenance expense in Exelons and Generations Consolidated Statements of Operations, representing the reduction in the ARO in excess of the existing ARC balances for the Non-Regulatory Agreement Units. Overview of Trust Funds. Trust funds have been established for each generating station unit to satisfy Generations nucl

Spent Nuclear Fuel Obligation

Spent Nuclear Fuel Obligation (Exelon and Generation)
	12 Months Ended Dec. 31, 2009 USD / shares
EXELON CORP
Spent Nuclear Fuel Obligation (Exelon and Generation)	12. Spent Nuclear Fuel Obligation (Exelon and Generation) Under the NWPA, the DOE is responsible for the development of a geologic repository for and the disposal of SNF and high-level radioactive waste. As required by the NWPA, Generation is a party to contracts with the DOE (Standard Contracts) to provide for disposal of SNF from Generations nuclear generating stations. In accordance with the NWPA and the Standard Contracts, Generation pays the DOE one mill ($.001) per kWh of net nuclear generation for the cost of SNF disposal. This fee may be adjusted prospectively in order to ensure full cost recovery. The NWPA and the Standard Contracts required the DOE to begin taking possession of SNF generated by nuclear generating units by no later than January31, 1998. The DOE, however, failed to meet that deadline and its performance will be delayed significantly. In January 2009, the DOE issued its Draft National Transportation Plan for the proposed repository. The DOEs press statement accompanying the release of the plan indicated that shipments to the repository are not expected to begin before 2020. The 2010 Federal budget (which became effective October1, 2009) eliminated almost all funding for the creation of the Yucca Mountain repository while the Obama Administration devises a new strategy for long-term SNF management. Debate surrounding any new strategy likely will address centralized interim storage, permanent storage at multiple sites and/or SNF reprocessing. Given the programs history of funding restrictions, it is possible that shipments to the repository may not begin by 2020. Because there is no particular date after 2020 that Generation can establish as having a higher probability as the start date for facility operations, Generation uses the 2020 date as its best estimate of when the DOE will begin accepting SNF. This extended delay in SNF acceptance by the DOE has led to Generations adoption of dry cask storage at its Dresden, Limerick, Oyster Creek, Peach Bottom, Byron, Braidwood, LaSalle and Quad Cities stations. Generation performed sensitivity analyses assuming that the estimated date for the DOE acceptance of SNF was delayed to 2025 and to 2035 and determined that Generations aggregate nuclear ARO would be reduced by an immaterial amount in each scenario. In August 2004, Generation and the U.S. DOJ, in close consultation with the DOE, reached a settlement under which the government agreed to reimburse Generation for costs associated with storage of SNF at Generations nuclear stations pending the DOEs fulfillment of its obligations. Generation submits annual reimbursement requests to the DOE for costs associated with the storage of SNF. In all cases, reimbursement requests are made only after costs are incurred and only for costs resulting from DOE delays in accepting the SNF. Under the agreement, Generation has received cash reimbursements for costs incurred through April30, 2009, totaling approximately $360 million ($282 million after considering amounts due to co-owners of certain nuclear stations and to the former owner of Oyster Creek). As of December31, 2009, the amount of SNF storage costs for which reimbu
EXELON GENERATION CO LLC
Spent Nuclear Fuel Obligation (Exelon and Generation)	12. Spent Nuclear Fuel Obligation (Exelon and Generation) Under the NWPA, the DOE is responsible for the development of a geologic repository for and the disposal of SNF and high-level radioactive waste. As required by the NWPA, Generation is a party to contracts with the DOE (Standard Contracts) to provide for disposal of SNF from Generations nuclear generating stations. In accordance with the NWPA and the Standard Contracts, Generation pays the DOE one mill ($.001) per kWh of net nuclear generation for the cost of SNF disposal. This fee may be adjusted prospectively in order to ensure full cost recovery. The NWPA and the Standard Contracts required the DOE to begin taking possession of SNF generated by nuclear generating units by no later than January31, 1998. The DOE, however, failed to meet that deadline and its performance will be delayed significantly. In January 2009, the DOE issued its Draft National Transportation Plan for the proposed repository. The DOEs press statement accompanying the release of the plan indicated that shipments to the repository are not expected to begin before 2020. The 2010 Federal budget (which became effective October1, 2009) eliminated almost all funding for the creation of the Yucca Mountain repository while the Obama Administration devises a new strategy for long-term SNF management. Debate surrounding any new strategy likely will address centralized interim storage, permanent storage at multiple sites and/or SNF reprocessing. Given the programs history of funding restrictions, it is possible that shipments to the repository may not begin by 2020. Because there is no particular date after 2020 that Generation can establish as having a higher probability as the start date for facility operations, Generation uses the 2020 date as its best estimate of when the DOE will begin accepting SNF. This extended delay in SNF acceptance by the DOE has led to Generations adoption of dry cask storage at its Dresden, Limerick, Oyster Creek, Peach Bottom, Byron, Braidwood, LaSalle and Quad Cities stations. Generation performed sensitivity analyses assuming that the estimated date for the DOE acceptance of SNF was delayed to 2025 and to 2035 and determined that Generations aggregate nuclear ARO would be reduced by an immaterial amount in each scenario. In August 2004, Generation and the U.S. DOJ, in close consultation with the DOE, reached a settlement under which the government agreed to reimburse Generation for costs associated with storage of SNF at Generations nuclear stations pending the DOEs fulfillment of its obligations. Generation submits annual reimbursement requests to the DOE for costs associated with the storage of SNF. In all cases, reimbursement requests are made only after costs are incurred and only for costs resulting from DOE delays in accepting the SNF. Under the agreement, Generation has received cash reimbursements for costs incurred through April30, 2009, totaling approximately $360 million ($282 million after considering amounts due to co-owners of certain nuclear stations and to the former owner of Oyster Creek). As of December31, 2009, the amount of SNF storage costs for which reimbu

Retirement Benefits

Retirement Benefits (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Retirement Benefits (Exelon, Generation, ComEd and PECO)	13. Retirement Benefits (Exelon, Generation, ComEd and PECO) As of December31, 2009, Exelon sponsored seven defined benefit pension plans and three postretirement benefit plans for essentially all Generation, ComEd, PECO and BSC employees. Exelons traditional and cash balance pension plans are intended to be tax-qualified defined benefit plans. Substantially all non-union employees and electing union employees hired on or after January1, 2001 participate in cash balance pension plans. Effective January1, 2009, substantially all newly hired union-represented employees participate in cash balance pension plans. Exelon has elected that the trusts underlying the plans be treated under the IRC as qualified trusts. If certain conditions are met, Exelon can deduct payments made to the qualified trusts, subject to certain IRC limitations. Exelon also sponsors certain non-qualified pension plans. Benefit Obligations and Plan Assets, and Funded Status Exelon recognizes the overfunded or underfunded status of defined benefit pension and other postretirement plans as an asset or liability on its balance sheet, with offsetting entries to Accumulated Other Comprehensive Income (AOCI) and regulatory assets, in accordance with the applicable authoritative guidance. The impact of changes in assumptions used to measure pension and other postretirement benefit obligations is generally recognized over the expected average remaining service period of the plan participants, rather than immediately recognized. The measurement date for the plans is December31. The obligations reflect the impact of Exelons 2009 restructuring activities and changes in certain plans related to some union participants. The following table provides a rollforward of the changes in the benefit obligations and plan assets for the most recent two years for all plans combined: Pension Benefits Other PostretirementBenefits 2009 2008 2009 2008 Change in benefit obligation: Net benefit obligation at beginning of year $ 10,788 $ 10,427 $ 3,480 $ 3,335 Service cost 178 163 113 108 Interest cost 651 635 205 208 Plan participants contributions 18 22 Actuarial loss (gain) 479 176 31 (14 ) Plan Amendments 2 16 Curtailments/settlements 2 1 Special termination benefits 4 Gross benefits paid (618 ) (630 ) (203 ) (189 ) Federal subsidy on benefits paid 10 10 Net benefit obligation at end of year $ 11,482 $ 10,788 $ 3,658 $ 3,480 Change in plan assets: Fair value of net plan assets at beginning of year $ 6,664 $ 9,634 $ 1,224 $ 1,616 Actual return on plan assets 1,352 (2,420 ) 280 (388 ) Employer contributions 441 80 157 163 Plan participants contributions 18

Corporate Restructuring and Pla

Corporate Restructuring and Plant Retirements (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Corporate Restructuring and Plant Retirements (Exelon, Generation, ComEd and PECO)	14. Corporate Restructuring and Plant Retirements (Exelon, Generation, ComEd and PECO) The Registrants provide severance and health and welfare benefits to terminated employees primarily based upon each individual employees years of service and compensation level. The Registrants accrue amounts associated with severance benefits that are considered probable and that can be reasonably estimated. The following table presents total severance benefits costs, recorded as operating and maintenance expense for the year ended December31, 2009: Severance Benefits Expense (a)(b) Generation ComEd PECO Other Exelon Corporate restructuring2009 $ 11 $ 19 $ 3 $ 1 $ 34 Plant retirements2009 (c) 7 7 Total severance benefits expense $ 18 $ 19 $ 3 $ 1 $ 41 (a) The amounts above include $7 million, $4 million, and $2 million at Generation, ComEd and PECO, respectively, for amounts billed through intercompany allocations for the year ended December31, 2009. (b) The severance benefits costs include $1 million of stock compensation expense collectively at Generation and ComEd for which the obligation is recorded in equity for the year ended December31, 2009, respectively. Severance benefits also include $4 million and $2 million at Exelon and ComEd, respectively, of contractual termination benefits expense for which the obligation is recorded in other postretirement benefits. (c) Severance-related expenses associated with plant retirements are described below. Corporate restructuring (Exelon, Generation, ComEd and PECO). On June18, 2009, Exelon announced a restructured senior executive team and major spending cuts, including the elimination of approximately 500 employee positions. Exelon eliminated approximately 400 corporate support positions, mostly located at corporate headquarters, and 100 management level positions at ComEd, the majority of which was completed by September30, 2009. These actions were in response to the continuing economic challenges confronting all parts of Exelons business and industry especially in light of the commodity-driven nature of Generations markets, necessitating continued focus on cost management through enhanced efficiency and productivity. Exelon recorded a pre-tax charge for estimated salary continuance and health and welfare severance benefits of $40 million in June 2009 as a result of the planned job reductions. Subsequent to June, Exelon recorded a net pre-tax credit of approximately $6 million, which included a $10 million reduction in estimated salary continuance and health and welfare severance benefits, offset by $4 million of expense for contractual termination benefits. Cash payments under the plan began in July 2009 and will continue through 2010. Substantially all cash payments are expected to be made by the end of 2010 or early 2011 resulting in the completion of the corporate restructuring plan. The following table presents the activity of severance obligations for the corporate restructuring from January1, 2009 t

Preferred Securities

Preferred Securities (Exelon, ComEd and PECO)
	12 Months Ended Dec. 31, 2009 USD / shares
EXELON CORP
Preferred Securities (Exelon, ComEd and PECO)	15. Preferred Securities (Exelon, ComEd and PECO) At December31, 2009 and 2008, Exelon was authorized to issue up to 100,000,000 shares of preferred securities, none of which were outstanding. Preferred and Preference Securities of Subsidiaries At December31, 2009 and 2008, ComEd prior preferred securities and ComEd cumulative preference securities consisted of 850,000 shares and 6,810,451 shares authorized, respectively, none of which were outstanding. At December31, 2009 and 2008, PECO cumulative preferred securities, no par value, consisted of 15,000,000 shares authorized and the outstanding amounts set forth below. Shares of preferred securities have full voting rights, including the right to cumulate votes in the election of directors. Redemption Price (a) December31, 2009 2008 2009 2008 Shares Outstanding DollarAmount Series (without mandatory redemption) $4.68 (Series D) $ 104.00 150,000 150,000 $ 15 $ 15 $4.40 (Series C) 112.50 274,720 274,720 27 27 $4.30 (Series B) 102.00 150,000 150,000 15 15 $3.80 (Series A) 106.00 300,000 300,000 30 30 Total preferred securities 874,720 874,720 $ 87 $ 87 (a) Redeemable, at the option of PECO, at the indicated dollar amounts per share, plus accrued dividends.
COMMONWEALTH EDISON CO
Preferred Securities (Exelon, ComEd and PECO)	15. Preferred Securities (Exelon, ComEd and PECO) At December31, 2009 and 2008, Exelon was authorized to issue up to 100,000,000 shares of preferred securities, none of which were outstanding. Preferred and Preference Securities of Subsidiaries At December31, 2009 and 2008, ComEd prior preferred securities and ComEd cumulative preference securities consisted of 850,000 shares and 6,810,451 shares authorized, respectively, none of which were outstanding. At December31, 2009 and 2008, PECO cumulative preferred securities, no par value, consisted of 15,000,000 shares authorized and the outstanding amounts set forth below. Shares of preferred securities have full voting rights, including the right to cumulate votes in the election of directors. Redemption Price (a) December31, 2009 2008 2009 2008 Shares Outstanding DollarAmount Series (without mandatory redemption) $4.68 (Series D) $ 104.00 150,000 150,000 $ 15 $ 15 $4.40 (Series C) 112.50 274,720 274,720 27 27 $4.30 (Series B) 102.00 150,000 150,000 15 15 $3.80 (Series A) 106.00 300,000 300,000 30 30 Total preferred securities 874,720 874,720 $ 87 $ 87 (a) Redeemable, at the option of PECO, at the indicated dollar amounts per share, plus accrued dividends.
PECO ENERGY CO
Preferred Securities (Exelon, ComEd and PECO)	15. Preferred Securities (Exelon, ComEd and PECO) At December31, 2009 and 2008, Exelon was authorized to issue up to 100,000,000 shares of preferred securities, none of which were outstanding. Preferred and Preference Securities of Subsidiaries At December31, 2009 and 2008, ComEd prior preferred securities and ComEd cumulative preference securities consisted of 850,000 shares and 6,810,451 shares authorized, respectively, none of which were outstanding. At December31, 2009 and 2008, PECO cumulative preferred securities, no par value, consisted of 15,000,000 shares authorized and the outstanding amounts set forth below. Shares of preferred securities have full voting rights, including the right to cumulate votes in the election of directors. Redemption Price (a) December31, 2009 2008 2009 2008 Shares Outstanding DollarAmount Series (without mandatory redemption) $4.68 (Series D) $ 104.00 150,000 150,000 $ 15 $ 15 $4.40 (Series C) 112.50 274,720 274,720 27 27 $4.30 (Series B) 102.00 150,000 150,000 15 15 $3.80 (Series A) 106.00 300,000 300,000 30 30 Total preferred securities 874,720 874,720 $ 87 $ 87 (a) Redeemable, at the option of PECO, at the indicated dollar amounts per share, plus accrued dividends.

Common Stock

Common Stock (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Common Stock (Exelon, Generation, ComEd and PECO)	16. Common Stock (Exelon, Generation, ComEd and PECO) At December31, 2009 and 2008, Exelons common stock without par value consisted of 2,000,000,000 shares authorized and 659,798,515 and 658,154,642 shares outstanding, respectively. At December31, 2009 and 2008, ComEds common stock with a $12.50 par value consisted of 250,000,000 shares authorized and 127,016,519 shares outstanding. At December31, 2009 and 2008, PECOs common stock without par value consisted of 500,000,000 shares authorized and 170,478,507 shares outstanding. ComEd had 75,294 and 75,410 warrants outstanding to purchase ComEd common stock as of December31, 2009 and 2008, respectively. The warrants entitle the holders to convert such warrants into common stock of ComEd at a conversion rate of one share of common stock for three warrants. At December31, 2009 and 2008, 25,098 and 25,137 shares of common stock, respectively, were reserved for the conversion of warrants. Share Repurchases Share Repurchase Programs. In April 2004, Exelons Board of Directors approved a discretionary share repurchase program that allows Exelon to repurchase shares of its common stock on a periodic basis in the open market. The share repurchase program is intended to mitigate, in part, the dilutive effect of shares issued under Exelons employee stock option plan and Exelons ESPP. The aggregate value of the shares of common stock repurchased pursuant to the program cannot exceed the economic benefit received after January1, 2004 due to stock option exercises and share purchases pursuant to Exelons ESPP. The economic benefit consists of the direct cash proceeds from purchases of stock and the tax benefits associated with exercises of stock options. The 2004 share repurchase program has no specified limit on the number of shares that may be repurchased and no specified termination date. Any shares repurchased are held as treasury shares unless cancelled or reissued at the discretion of Exelons management. During 2008, 6.6million shares of common stock were purchased under this share repurchase program for $500 million. On August31 and December19, 2007, Exelons Board of Directors approved a share repurchase program for up to $1.25billion and $500 million of Exelons outstanding common stock, respectively. In 2007, Exelon entered into agreements to repurchase a total of $1.25billion of Exelons common shares under the first accelerated share repurchase (ASR) program, and 2008, Exelon entered into an agreement to repurchase a total of $500 million of Exelons common shares under the second ASR program. Exelon accounted for each ASR program as two distinct transactions, as shares of common stock acquired in a treasury stock transaction and as a forward contract indexed to Exelons own common stock. The ASR agreements include a pricing collar, which establishes a minimum and maximum number of shares that can be repurchased. In September2007 and February 2008. Exelon received the minimum number of shares, as determined by each of the ASR agreements, which amounted to 15.1million shares and 5.8million shares, respectively. These initial shares were recorded as treasury stock, at cost, for $1.17

Earnings Per Share and Equity (

Earnings Per Share and Equity (Exelon) (EXELON CORP)
	12 Months Ended Dec. 31, 2009 USD / shares
Earnings Per Share and Equity (Exelon)	17.Earnings Per Share and Equity (Exelon) Earnings per Share Diluted earnings per share is calculated by dividing net income by the weighted average number of shares of common stock outstanding, including shares to be issued upon exercise of stock options, performance share awards and restricted stock outstanding under Exelons LTIPs considered to be common stock equivalents. The following table sets forth the components of basic and diluted earnings per share and shows the effect of these stock options, performance share awards and restricted stock on the weighted average number of shares outstanding used in calculating diluted earnings per share: 2009 2008 2007 Income from continuing operations $ 2,706 $ 2,717 $ 2,726 Income from discontinued operations 1 20 10 Net income $ 2,707 $ 2,737 $ 2,736 Average common shares outstandingbasic 659 658 670 Assumed exercise and/or distributions of stock-based awards 3 4 6 Average common shares outstandingdiluted 662 662 676 The number of stock options not included in the calculation of diluted common shares outstanding due to their antidilutive effect was approximately 5million in 2009 and less than 1million in 2008 and 2007.

Commitments and Contingencies

Commitments and Contingencies (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Commitments and Contingencies (Exelon, Generation, ComEd and PECO)	18. Commitments and Contingencies (Exelon, Generation, ComEd and PECO) Nuclear Insurance The Price-Anderson Act was enacted to limit the liability of nuclear reactor owners for claims that could arise from a single incident at any of the U.S. licensed nuclear facilities and to ensure the availability of funds for claims arising in the event of an incident. As of December31, 2009, the current liability limit per incident was $12.6 billion and is subject to change to account for the effects of inflation and changes in the number of licensed reactors. As required by the Price-Anderson Act, Generation maintains a primary level of financial protection by carrying the maximum available amount of nuclear liability insurance for claims that could arise in the event of an incident. As of January1, 2010, the required amount of nuclear liability insurance is $375 million for each operating site. Additionally, the Price-Anderson Act requires a second layer of protection through the mandatory participation in a secondary financial protection pool by the operators of all U.S. licensed reactors (currently 104 reactors) resulting in an additional $12.2 billion in funds available for claims. Participation in the financial protection pool requires the operator of each reactor to fund its proportionate share of costs for any single incident that exceeds the primary layer of insurance coverage. Under the Price-Anderson Act, the maximum assessment, in the event of an incident for each nuclear operator per reactor per incident (including a 5% surcharge) is $117.5 million, payable at no more than $17.5 million per reactor per incident per year. Exelons maximum liability per incident is approximately $2.0 billion.In addition, the U.S. Congress could impose revenue-raising measures on the nuclear industry to pay claims. The Price-Anderson Act, as amended, requires an inflation adjustment be made at least once each 5 years. The last inflation adjustment was effective October29, 2008. Generation is a member of an industry mutual insurance company, Nuclear Electric Insurance Limited (NEIL), which provides property damage, decontamination and premature decommissioning insurance for each station for losses resulting from damage to its nuclear plants, either due to accidents or acts of terrorism. Generations current limit for this coverage is $2.1 billion (except for Zion, which is $100 million). For property limits in excess of the first $1.25 billion of that limit, Generation participates in an $850 million single limit blanket policy shared by all the Generation operating nuclear sites and the Salem and Hope Creek nuclear sites. This blanket limit is not subject to automatic reinstatement in the event of a loss. In the event of an accident, insurance proceeds must first be used for reactor stabilization and site decontamination. If the decision is made to decommission the facility, a portion of the insurance proceeds will be allocated to a fund, which Generation is required by the NRC to maintain, to provide for decommissioning the facility. Generation is unable to predict the timing of the availability of insurance proceeds to Generation and the amount of

Supplemental Financial Informat

Supplemental Financial Information (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Supplemental Financial Information (Exelon, Generation, ComEd and PECO)	19. Supplemental Financial Information (Exelon, Generation, ComEd and PECO) Supplemental Income Statement Information The following tables provide additional information about the Registrants Consolidated Statements of Operations for the years ended December31, 2009, 2008 and 2007. For the Year Ended December31, 2009 Exelon Generation ComEd PECO Operating revenues (a) Wholesale $ 5,469 $ 8,905 $ $ 26 Retail electric and gas 11,099 838 (b) 5,220 5,049 Other 750 (40 )(c) 554 236 Total operating revenues $ 17,318 $ 9,703 $ 5,774 $ 5,311 For the Year Ended December31, 2008 Exelon Generation ComEd PECO Operating revenues (a) Wholesale $ 6,394 $ 9,934 $ $ 45 Retail electric and gas 11,816 979 (b) 5,563 5,278 Other 649 (159 )(c) 573 244 Total operating revenues $ 18,859 $ 10,754 $ 6,136 $ 5,567 For the Year Ended December31, 2007 Exelon Generation ComEd PECO Operating revenues (a) Wholesale $ 6,550 $ 9,970 $ 58 $ 61 Retail electric and gas 11,750 909 (b) 5,543 5,300 Other 616 (130 )(c)(d) 503 252 Total operating revenues $ 18,916 $ 10,749 $ 6,104 $ 5,613 (a) Includes operating revenues from affiliates. (b) Generations retail electric and gas operating revenues consist solely of Exelon Energy Company, LLC. (c) Includes amounts recorded related to the Illinois Settlement. (d) Includes income associated with the termination of Generations PPA with State Line. For the Year Ended December31, 2009 Exelon Generation ComEd PECO Depreciation, amortization and accretion Property, plant and equipment $ 996 $ 333 $ 446 $ 162 Regulatory assets (a) 838 48 790 Nuclear fuel (b) 558 558 ARO accretion (c) 209 207 1 Total depreciation, amortization and accretion $ 2,601 $ 1,098 $ 495 $ 952 For the Year Ended December31, 2008 Exelon Generation ComEd PECO Depreciation, amortization and accretion Property, plant and equipment $ 898 $ 274 $ 424 $ 158 Regulatory assets (a) 736 40 696 Nuclear fuel (b) 448 448 ARO accretion (c) 226 225 1 Total depreciation, amortization and accretion $ 2,308 $ 947 $ 465 $ 854 For the Year Ended December31, 2007 Exelon Generation ComEd PECO Depreciation, amortization and accretion Property, plant and equipment $ 856 $ 266 $ 400 $ 149

Segment Information

Segment Information (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Segment Information (Exelon, Generation, ComEd and PECO)	20. Segment Information (Exelon, Generation, ComEd and PECO) Exelon has three operating segments: Generation, ComEd and PECO. Exelon evaluates the performance of its business segments based on net income. Generation, ComEd and PECO each represent a single reportable segment; as such, no separate segment information is provided for these Registrants. PECO has two operating segments, electric and gas delivery, which are aggregated into one reportable segment primarily due to their similar economic characteristics and the regulatory environments in which they operate. An analysis and reconciliation of Exelons operating segment information to the respective information in the consolidated financial statements are as follows: Generation ComEd PECO Other Intersegment Eliminations Consolidated Total revenues (a) : 2009 $ 9,703 $ 5,774 $ 5,311 $ 757 $ (4,227 ) $ 17,318 2008 10,754 6,136 5,567 697 (4,295 ) 18,859 2007 10,749 6,104 5,613 741 (4,291 ) 18,916 Intersegment revenues (b): 2009 $ 3,472 $ 2 $ 6 $ 756 $ (4,227 ) $ 9 2008 3,586 4 10 695 (4,295 ) 2007 3,538 2 11 740 (4,291 ) Depreciation and amortization 2009 $ 333 $ 494 $ 952 $ 55 $ $ 1,834 2008 274 464 854 42 1,634 2007 267 440 773 40 1,520 Operating expenses (a): 2009 $ 6,408 $ 4,931 $ 4,614 $ 840 $ (4,225 ) $ 12,568 2008 6,760 5,469 4,868 758 (4,295 ) 13,560 2007 7,357 5,592 4,666 924 (4,291 ) 14,248 Interest expense, net: 2009 $ 113 $ 319 $ 187 $ 112 $ $ 731 2008 136 348 226 132 (10 ) 832 2007 161 318 248 124 (1 ) 850 Income(loss)from continuing operations before income taxes: 2009 $ 3,555 $ 603 $ 499 $ (236 ) $ (3 ) $ 4,418 2008 3,388 329 475 (158 ) 4,034 2007 3,387 245 737 (197 ) 4,172 Income taxes: 2009 $ 1,433 $ 229 $ 146 $ (102 ) $ 6 $ 1,712 2008 1,130 128 150 (91 ) 1,317 2007 1,362 80 230 (226 ) 1,446 Generation ComEd PECO Other Intersegment Eliminations Consolidated Income (loss) from continuing operations: 2009 $ 2,122 $ 374 $ 353 $ (134 ) $ (9 ) $ 2,706 2008 2,258 201 325 (67 ) 2,717 2007 2,025 165 507 29 2,726 Income(loss)from discontin

Related-Party Transactions

Related-Party Transactions (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Related-Party Transactions (Exelon, Generation, ComEd and PECO)	21.Related-Party Transactions (Exelon, Generation, ComEd and PECO) Exelon The financial statements of Exelon include related-party transactions as presented in the tables below: For the Years Ended December31, 2009 2008 2007 Operating revenues from affiliates CTFT (a) $ $ 3 $ 3 PETT 3 5 6 PECO (b) 9 Other 1 Total operating revenues from affiliates $ 12 $ 8 $ 10 Fuel purchases from related parties Keystone Fuels, LLC $ 56 $ 73 $ 46 Conemaugh Fuels, LLC 69 54 46 Total fuel purchases from related parties $ 125 $ 127 $ 92 Charitable contribution to Exelon Foundation (d) $ 10 $ $ 50 Interest expense to affiliates, net CTFT (a) $ $ 6 $ 27 ComEd Financing II (c) 2 13 ComEd Financing III 13 13 13 PETT 51 101 139 PECO Trust III 6 6 6 PECO Trust IV 6 6 6 Other 1 (1 ) (1 ) Total interest expense to affiliates, net $ 77 $ 133 $ 203 Equity in earnings (losses) of unconsolidated affiliates and investments ComEd Funding (a) $ $ (8 ) $ (7 ) PETT (24 ) (16 ) (7 ) NuStart Energy Development, LLC (3 ) TEG and TEP (e) 3 Investment in synthetic fuel-producing facilities (93 ) Other (2 ) (2 ) Total equity in losses of unconsolidated affiliates and investments $ (27 ) $ (26 ) $ (106 ) As of December31, 2009 As of December31, 2008 Investments in affiliates ComEd Financing III $ 7 $ 6 PETT 5 30 PECO Energy Capital Corporation 4 4 PECO Trust IV 4 5 Total investments in affiliates $ 20 $ 45 Payables to affiliates (current) ComEd Financing III $ 4 $ 4 PECO Trust III 1 1 Total payables to affiliates (current) $ 5 $ 5 Long-term debt to PETT and other financing trusts (including due within one year) ComEd Financing III $ 206 $ 206 PETT 415 1,124 PECO Trust III 81 81 PECO Trust IV 103 103 Total long-term debt due to financing trusts $ 805 $ 1,514 (a) During 2008, ComEd fully paid its long-term debt obligations to CTFT and received its current receivable from CTFT. ComEd Funding liquidated its investment in CTFT and ComEd liquidated its investment in ComEd Funding. This resulted in the elimination of operating revenues and interest expense applicable to CTFT, and equity in losses of the unconsolidated affiliate, ComEd Fun

Quarterly Data (Unaudited)

Quarterly Data (Unaudited) (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Quarterly Data (Unaudited) (Exelon, Generation, ComEd and PECO)	22. Quarterly Data (Unaudited) (Exelon, Generation, ComEd and PECO) Exelon The data shown below includes all adjustments which Exelon considers necessary for a fair presentation of such amounts: OperatingRevenues Operating Income Net Income 2009 2008 2009 2008 2009 2008 Quarter ended: March 31 $ 4,722 $ 4,517 $ 1,254 $ 1,123 $ 712 $ 581 June 30 4,141 4,622 1,017 1,430 657 748 September 30 4,339 5,228 1,403 1,413 757 700 December 31 4,116 4,493 1,076 1,333 581 707 AverageBasicShares Outstanding (in millions) Net Income per Basic Share 2009 2008 2009 2008 Quarter ended: March 31 659 659 $ 1.08 $ 0.88 June 30 659 657 1.00 1.14 September 30 660 658 1.15 1.06 December 31 660 658 0.88 1.07 AverageDilutedShares Outstanding (in millions) Net Income perDilutedShare 2009 2008 2009 2008 Quarter ended: March 31 661 664 $ 1.08 $ 0.88 June 30 661 662 0.99 1.13 September 30 662 662 1.14 1.06 December 31 662 661 0.88 1.07 The following table presents the New York Stock ExchangeComposite Common Stock Prices and dividends by quarter on a per share basis: 2009 2008 Fourth Quarter Third Quarter Second Quarter First Quarter Fourth Quarter Third Quarter Second Quarter First Quarter High price $ 51.98 $ 54.47 $ 51.46 $ 58.98 $ 63.84 $ 92.13 $ 91.84 $ 87.25 Low price 45.90 47.30 44.24 38.41 41.23 60.00 81.00 70.00 Close 48.87 49.62 50.12 45.39 55.61 62.62 89.96 81.27 Dividends 0.525 0.525 0.525 0.525 0.525 0.500 0.500 0.500 Generation The data shown below includes all adjustments that Generation considers necessary for a fair presentation of such amounts: OperatingRevenues Operating Income Net Income 2009 2008 2009 2008 2009 2008 Quarter ended: March 31 $ 2,601 $ 2,482 $ 862 $ 739 $ 528 $ 438 June 30 2,378 2,756 676 1,138 512 653 September 30 2,445 3,073 1,046 1,140 657 635 December 31 2,278 2,443 711 976 425 553 ComEd The data shown below includes all adjustments that ComEd considers necessary for a fair presentation of such amounts: OperatingRevenues OperatingIncome Net Income 2009 2008 2009 2008 2009 2008 Quarter ended: March 31 $ 1,553 $ 1,440 $ 206 $ 170 $ 114 $ 41 June 30 1,389 1,425 209 141 116 35 September 30 1,475 1,729 203 138 46 33 December

Schedule I Exelon Corporate Fin

Schedule I Exelon Corporate Financial Statements (Exelon) (EXELON CORP)
	12 Months Ended Dec. 31, 2009 USD / shares
Schedule I Exelon Corporate Financial Statements (Exelon)	EXELON CORPORATION AND SUBSIDIARY COMPANIES Schedule I Exelon Corporate Statements of Operations For the Years Ended December31, (In millions) 2009 2008 2007 Operating expenses Operating and maintenance $ 45 $ 19 $ 51 Operating and maintenance from affiliates 35 31 31 Total operating expenses 80 50 82 Operating loss (80 ) (50 ) (82 ) Other income and (deductions) Interest expense, net of amounts capitalized (133 ) (127 ) (144 ) Equity in earnings of investments 2,835 2,817 2,806 Interest Income from affiliates, net 2 2 Other, net (42 ) 9 26 Total other income and deductions 2,660 2,701 2,690 Income from continuing operations before income taxes 2,580 2,651 2,608 Income taxes (127 ) (86 ) (128 ) Net income $ 2,707 $ 2,737 $ 2,736 Exelon Corporate Condensed Statements of Cash Flows For the Years Ended December31, (In millions) 2009 2008 2007 Net cash flows provided by operating activities $ 2,767 $ 2,245 $ 3,090 Cash flows from investing activities Changes in Exelon intercompany money pool 31 (37 ) 47 Change in note receivable from affiliate 67 Investment in affiliates (454 ) (640 ) (871 ) Net cash flows used in investing activities (423 ) (677 ) (757 ) Cash flows from financing activities Change in short-term debt (56 ) 56 (150 ) Retirement of long-term debt (500 ) Dividends paid on common stock (1,385 ) (1,335 ) (1,180 ) Proceeds from employee stock plans 42 130 215 Purchase of treasury stock (436 ) (1,208 ) Purchase of forward contract in relation to certain treasury stock (64 ) (79 ) Other financing activities 7 61 105 Net cash flows used in financing activities (1,892 ) (1,588 ) (2,297 ) Increase (decrease) in cash and cash equivalents 452 (20 ) 36 Cash and cash equivalents at beginning of period 21 41 5 Cash and cash equivalents at end of period $ 473 $ 21 $ 41 Exelon Corporate Balance Sheets December31, (In millions) 2009 2008 Assets Current assets Cash and cash equivalents $ 473 $ 21 Accounts receivable, net Other accounts receivable 108 105 Accounts receivable from affiliates 11 53 Notes receivables from affilia

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts (Exelon, Generation, ComEd and PECO)
	12 Months Ended Dec. 31, 2009
Schedule II - Valuation and Qualifying Accounts (Exelon, Generation, ComEd and PECO)	EXELON CORPORATION AND SUBSIDIARY COMPANIES Schedule II Valuation and Qualifying Accounts (in millions) Column A Column B Column C Column D Column E Description Balanceat Beginning of Year Additionsandadjustments Deductions Balanceat EndofYear Charged to Cost and Expenses Charged to Other Accounts For The Year Ended December31, 2009 Allowance for uncollectible accounts $ 238 $ 150 $ 38 (a) $ 201 (b) $ 225 Deferred tax valuation allowance 29 9 2 36 Reserve for obsolete materials 28 19 2 45 For The Year Ended December31, 2008 Allowance for uncollectible accounts $ 130 $ 247 $ 31 (a) $ 170 (b) $ 238 Deferred tax valuation allowance 33 4 29 Reserve for obsolete materials 29 2 2 5 28 For The Year Ended December31, 2007 Allowance for uncollectible accounts $ 91 $ 132 $ 17 (a) $ 110 (b) $ 130 Deferred tax valuation allowance 37 4 33 Reserve for obsolete materials 27 4 2 29 (a) Primarily charges for late payments and non-service receivables. (b) Write-off of individual accounts receivable. EXELON GENERATION COMPANY, LLC AND SUBSIDIARY COMPANIES Schedule II Valuation and Qualifying Accounts (in millions) (2) Generation (i) Financial Statements Consolidated Statements of Operations for the years 2009, 2008 and 2007 Consolidated Statements of Cash Flows for the years 2009, 2008 and 2007 Consolidated Balance Sheets as of December 31, 2009 and 2008 Consolidated Statements of Changes in Members Equity for the years 2009, 2008 and 2007 Consolidated Statements of Comprehensive Income for the years 2009, 2008 and 2007 Notes to Consolidated Financial Statements (ii) Financial Statement Schedule EXELON GENERATION COMPANY, LLC AND SUBSIDIARY COMPANIES Schedule II Valuation and Qualifying Accounts (in millions) Column A Column B Column C Column D Column E Description Balanceat Beginning of Year Additionsandadjustments Deductions Balanceat EndofYear Charged to Cost and Expenses Charged to Other Accounts For The Year Ended December31, 2009 Allowance for uncollectible accounts $ 30 $ 2 $ $ 1 $ 31 Deferred tax valuation allowance 20 2 18 Reserve for obsolete materials 26 17 43 For The Year Ended December31, 2008 Allowance for uncollectible accounts $ 17 $ 17 $ (3 ) $ 1 $ 30 Deferred tax valuation allowance 32 12 20 Reserve for obsolet

Document Information

Document Information
	12 Months Ended Dec. 31, 2009
Document Type	10-K
Amendment Flag	false
Document Period End Date	2009-12-31

Entity Information

Entity Information (USD $)
	12 Months Ended Dec. 31, 2009	Jan. 29, 2010	Jun. 30, 2009
Trading Symbol	EXC
Entity Registrant Name	EXELON CORP
Entity Central Index Key	0001109357
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		659,895,066
Entity Public Float			$33,730,940,743
EXELON GENERATION CO LLC
Entity Registrant Name	EXELON GENERATION CO LLC
Entity Central Index Key	0001168165
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
COMMONWEALTH EDISON CO
Entity Registrant Name	COMMONWEALTH EDISON CO
Entity Central Index Key	0000022606
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		127,016,519
PECO ENERGY CO
Entity Registrant Name	PECO ENERGY CO
Entity Central Index Key	0000078100
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		170,478,507