Unaudited Condensed Consolidated Statements of Income (USD $) In Millions, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Statement Of Income [Line Items]
Operating revenues	$ 2,747	$ 2,962	$ 7,170	$ 7,869
Operating expenses
Fuel used in electric generation	844	935	2,236	2,574
Purchased power	349	418	898	996
Operation and maintenance	487	474	1,491	1,459
Depreciation, amortization and accretion	175	201	508	680
Taxes other than on income	163	161	437	448
Other	39	20	31	25
Total operating expenses	2,057	2,209	5,601	6,182
Operating income	690	753	1,569	1,687
Other income (expense)
Interest income	1	3	2	6
Allowance for equity funds used during construction	22	22	77	68
Other, net	(70)	(5)	(60)	(5)
Total other income, net	(47)	20	19	69
Interest charges
Interest charges	180	197	568	587
Allowance for borrowed funds used during construction	(8)	(8)	(26)	(24)
Total interest charges, net	172	189	542	563
Income from continuing operations before income tax	471	584	1,046	1,193
Income tax expense	178	219	386	456
Equity in earnings of consolidated subsidiaries	0	0	0	0
Income from continuing operations before cumulative effect of change in accounting principle	293	365	660	737
Discontinued operations, net of tax	0	(2)	(4)	(2)
Cumulative effect of change in accounting principle, net of tax	0	2	0	0
Net income	293	365	656	735
Net (income) loss attributable to noncontrolling interests, net of tax	(2)	(4)	(5)	(4)
Net income attributable to controlling interests	291	361	651	731
Average common shares outstanding - basic	296	294	296	289
Basic and diluted earnings per common share
Income from continuing operations attributable to controlling interests, net of tax	$ 0.98	$ 1.23	$ 2.22	$ 2.53
Discontinued operations attributable to controlling interests, net of tax	$ 0.00	$ 0.00	$ (0.02)	$ 0.00
Net income attributable to controlling interests	$ 0.98	$ 1.23	$ 2.20	$ 2.53
Dividends declared per common share	$ 0.620	$ 0.620	$ 1.860	$ 1.860
Amounts attributable to controlling interests
Income from continuing operations, net of tax	291	363	655	733
Discontinued operations, net of tax	0	(2)	(4)	(2)
Net income attributable to controlling interests	291	361	651	731
PEC
Statement Of Income [Line Items]
Operating revenues	1,332	1,414	3,525	3,794
Operating expenses
Fuel used in electric generation	388	464	1,077	1,322
Purchased power	117	109	257	235
Operation and maintenance	271	256	859	841
Depreciation, amortization and accretion	132	120	382	358
Taxes other than on income	57	58	163	169
Other	38	5	38	5
Total operating expenses	1,003	1,012	2,776	2,930
Operating income	329	402	749	864
Other income (expense)
Interest income	0	1	1	3
Allowance for equity funds used during construction	15	17	53	45
Other, net	(4)	(2)	(5)	(5)
Total other income, net	11	16	49	43
Interest charges
Interest charges	45	51	149	154
Allowance for borrowed funds used during construction	(4)	(5)	(15)	(14)
Total interest charges, net	41	46	134	140
Income from continuing operations before income tax	299	372	664	767
Income tax expense	100	138	227	284
Income from continuing operations before cumulative effect of change in accounting principle	199	234	437	483
Cumulative effect of change in accounting principle, net of tax	0	2	0	0
Net income	199	236	437	483
Net (income) loss attributable to noncontrolling interests, net of tax	0	(2)	0	1
Net income attributable to controlling interests	199	234	437	484
Preferred stock dividend requirement	(1)	(1)	(2)	(2)
Net income available to parent	198	233	435	482
Amounts attributable to controlling interests
Net income attributable to controlling interests	199	234	437	484
PEF
Statement Of Income [Line Items]
Operating revenues	1,414	1,543	3,639	4,065
Operating expenses
Fuel used in electric generation	456	471	1,159	1,252
Purchased power	232	309	641	761
Operation and maintenance	221	234	655	647
Depreciation, amortization and accretion	39	77	112	311
Taxes other than on income	106	102	274	278
Other	(1)	6	(13)	6
Total operating expenses	1,053	1,199	2,828	3,255
Operating income	361	344	811	810
Other income (expense)
Interest income	1	0	1	1
Allowance for equity funds used during construction	7	5	24	23
Other, net	(1)	(3)	3	0
Total other income, net	7	2	28	24
Interest charges
Interest charges	50	68	187	202
Allowance for borrowed funds used during construction	(4)	(3)	(11)	(10)
Total interest charges, net	46	65	176	192
Income from continuing operations before income tax	322	281	663	642
Income tax expense	119	101	245	241
Net income	203	180	418	401
Preferred stock dividend requirement	0	0	(1)	(1)
Net income available to parent	$ 203	$ 180	$ 417	$ 400