Unaudited Condensed Consolidated Statements of Comprehensive Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Statement of Comprehensive Income [Line Items]
Operating revenues	$ 2,092	$ 2,167
Operating expenses
Fuel used in electric generation	685	718
Purchased power	210	220
Operation and maintenance	529	494
Depreciation, amortization and accretion	166	154
Taxes other than on income	138	140
Other	0	(10)
Total operating expenses	1,728	1,716
Operating income	364	451
Other income (expense)
Interest income	1	1
Allowance for equity funds used during construction	24	29
Other, net	13	3
Total other income, net	38	33
Interest charges
Interest charges	194	199
Allowance for borrowed funds used during construction	(9)	(9)
Total interest charges, net	185	190
Income from continuing operations before income tax	217	294
Income tax expense	76	107
Income from continuing operations	141	187
Discontinued operations, net of tax	11	(2)
Net income	152	185
Net income attributable to noncontrolling interests, net of tax	(2)	(1)
Net income attributable to controlling interests	150	184
Average common shares outstanding - basic	297	295
Basic and diluted earnings per common share
Income from continuing operations attributable to controlling interests, net of tax	$ 0.47	$ 0.63
Discontinued operations attributable to controlling interests, net of tax	$ 0.04	$ (0.01)
Net income attributable to controlling interests	$ 0.51	$ 0.62
Dividends declared per common share	$ 0.620	$ 0.620
Net income amounts attributable to controlling interests
Income from continuing operations, net of tax	139	186
Discontinued operations, net of tax	11	(2)
Net income attributable to controlling interests	150	184
Comprehensive income
Comprehensive income	157	189
Comprehensive (income) loss attributable to noncontrolling interests, net of tax	(2)	(1)
Comprehensive income attributable to controlling interests	155	188
PEC
Statement of Comprehensive Income [Line Items]
Operating revenues	1,085	1,133
Operating expenses
Fuel used in electric generation	349	363
Purchased power	65	67
Operation and maintenance	374	295
Depreciation, amortization and accretion	134	124
Taxes other than on income	56	56
Other	(1)	0
Total operating expenses	977	905
Operating income	108	228
Other income (expense)
Allowance for equity funds used during construction	15	20
Other, net	4	(2)
Total other income, net	19	18
Interest charges
Interest charges	56	50
Allowance for borrowed funds used during construction	(5)	(5)
Total interest charges, net	51	45
Income from continuing operations before income tax	76	201
Income tax expense	24	70
Net income	52	131
Preferred stock dividend requirement	(1)	(1)
Net income available to parent	51	130
Comprehensive income
Comprehensive income attributable to controlling interests	57	133
PEF
Statement of Comprehensive Income [Line Items]
Operating revenues	1,005	1,032
Operating expenses
Fuel used in electric generation	336	355
Purchased power	145	153
Operation and maintenance	160	210
Depreciation, amortization and accretion	27	25
Taxes other than on income	82	85
Other	0	(12)
Total operating expenses	750	816
Operating income	255	216
Other income (expense)
Allowance for equity funds used during construction	9	9
Other, net	0	3
Total other income, net	9	12
Interest charges
Interest charges	67	69
Allowance for borrowed funds used during construction	(4)	(4)
Total interest charges, net	63	65
Income from continuing operations before income tax	201	163
Income tax expense	73	61
Net income	128	102
Preferred stock dividend requirement	(1)	(1)
Net income available to parent	127	101
Comprehensive income
Comprehensive income attributable to controlling interests	$ 129	$ 102