Condensed Consolidating Statements (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Dec. 31, 2009
Operating revenues
Operating revenues	$ 2,256	$ 2,372	$ 4,423	$ 4,907
Affiliate revenues	0	0	0	0
Total operating revenues	2,256	2,372	4,423	4,907
Operating expenses
Fuel used in electric generation	674	743	1,392	1,639
Purchased power	329	315	549	578
Operation and maintenance	510	505	1,004	985
Depreciation, amortization and accretion	179	233	333	479
Taxes other than on income	134	133	274	287
Other	2	3	(8)	5
Total operating expenses	1,828	1,932	3,544	3,973
Operating (loss) income	428	440	879	934
Other income (expense)
Interest income	0	1	1	3
Allowance for equity funds used during construction	26	25	55	46
Other, net	7	5	10	0
Total other income (expense), net	33	31	66	49
Interest charges
Interest charges	189	199	388	390
Allowance for borrowed funds used during construction	(9)	(7)	(18)	(16)
Total interest charges, net	180	192	370	374
(Loss) income from continuing operations before income tax and equity in earnings of consolidated subsidiaries	281	279	575	609
Income tax (benefit) expense	101	98	208	237
Equity in earnings of consolidated subsidiaries	0	0	0	0
Income from continuing operations before cumulative effect of change in accounting principle	180	181	367	372
Discontinued operations, net of tax	(2)	(1)	(4)	0
Cumulative effect of change in accounting principle, net of tax	0	0	0	(2)
Net income (loss)	178	180	363	370
Net (income) loss attributable to noncontrolling interests, net of tax	(2)	0	(3)	0
Net income attributable to controlling interests	176	180	360	370
ASSETS
Utility plant, net	21,749		21,749		21,240
Current assets
Cash and cash equivalents	52	690	52	690
Receivables, net	1,041		1,041		1,033
Notes receivable from affiliated companies	0		0		0
Regulatory assets	198		198		176
Derivative collateral posted	122		122		164
Prepayments and other current assets	1,603		1,603		1,492
Total current assets	3,016		3,016		3,476
Deferred debits and other assets
Investment in consolidated subsidiaries	0		0		0
Regulatory assets	2,268		2,268		2,374
Goodwill	3,655		3,655		3,655
Nuclear decommissioning trust funds	1,686		1,686		1,571
Other assets and deferred debits	746		746		738
Total deferred debits and other assets	8,355		8,355		8,338
Total assets	33,120		33,120		33,054
Equity
Common stock equity	10,046		10,046		10,023
Noncontrolling interests	3		3		4
Total equity	10,049	9,859	10,049	9,859	10,027	9,455
Preferred stock of subsidiaries	93		93		93
Long-term debt, affiliate	273		273		273
Long-term debt, net	11,418		11,418		11,864
Total capitalization	21,833		21,833		22,257
Current liabilities
Current portion of long-term debt	750		750		505
Short-term debt	314		314		0
Notes payable to affiliated companies	0		0		0
Derivative liabilities	214		214		259
Other current liabilities	2,179		2,179		2,191
Total current liabilities	3,457		3,457		2,955
Deferred credits and other liabilities
Noncurrent income tax liabilities	1,902		1,902		1,696
Regulatory liabilities	2,585		2,585		2,635
Other liabilities and deferred credits	3,343		3,343		3,511
Total deferred credits and other liabilities	7,830		7,830		7,842
Total capitalization and liabilities	33,120		33,120		33,054
Condensed Consolidating Statement of Cash Flows
Net cash provided (used) by operating activities			780	1,159
Investing activities
Gross property additions			(1,004)	(1,116)
Nuclear fuel additions			(93)	(119)
Proceeds from sales of assets to affiliated companies				0
Purchases of available-for-sale securities and other investments			(3,387)	(3,815)
Proceeds from available-for-sale securities and other investments			3,364	3,792
Changes in advances to affiliated companies			0	0
Return of investment in consolidated subsidiaries			0	0
Contributions to consolidated subsidiaries			0	0
Other investing activities			82	14
Net cash provided (used) by investing activities			(1,038)	(1,244)
Financing activities
Issuance of common stock, net			26	405
Dividends paid on common stock			(366)	(354)
Dividends paid to parent			0	0
Dividends paid to parent in excess of retained earnings			0	0
Net increase (decrease) in short-term debt			314	(140)
Proceeds from issuance of long-term debt, net			494	591
Retirement of long-term debt			(700)	(400)
Changes in advances from affiliated companies			0	0
Contributions from parent			0	0
Other financing activities			(69)	(52)
Net cash provided (used) by financing activities			(301)	50
Net increase (decrease) in cash and cash equivalents			(559)	(35)
Cash and cash equivalents at beginning of period			611	725
Cash and cash equivalents at end of period	52	690	52	690
Parent
Operating revenues
Operating revenues	0	0	0	0
Affiliate revenues	0	0	0	0
Total operating revenues	0	0	0	0
Operating expenses
Fuel used in electric generation	0	0	0	0
Purchased power	0	0	0	0
Operation and maintenance	1	0	4	3
Depreciation, amortization and accretion	0	0	0	0
Taxes other than on income	0	0	0	0
Other	0	0	0	0
Total operating expenses	1	0	4	3
Operating (loss) income	(1)	0	(4)	(3)
Other income (expense)
Interest income	0	2	0	4
Allowance for equity funds used during construction	0	0	0	0
Other, net	4	0	4	(1)
Total other income (expense), net	4	2	4	3
Interest charges
Interest charges	63	72	136	143
Allowance for borrowed funds used during construction	0	0	0	0
Total interest charges, net	63	72	136	143
(Loss) income from continuing operations before income tax and equity in earnings of consolidated subsidiaries	(60)	(70)	(136)	(143)
Income tax (benefit) expense	(24)	(28)	(55)	(58)
Equity in earnings of consolidated subsidiaries	212	222	441	455
Income from continuing operations before cumulative effect of change in accounting principle	176	180	360	370
Discontinued operations, net of tax	0	0	0	0
Cumulative effect of change in accounting principle, net of tax	0		0	0
Net income (loss)	176	180	360	370
Net (income) loss attributable to noncontrolling interests, net of tax	0	0	0	0
Net income attributable to controlling interests	176	180	360	370
ASSETS
Utility plant, net	0		0		0
Current assets
Cash and cash equivalents	0	366	0	366
Receivables, net	0		0		0
Notes receivable from affiliated companies	94		94		14
Regulatory assets	0		0		0
Derivative collateral posted	0		0		0
Income taxes receivable	0		0		0
Prepayments and other current assets	42		42		30
Total current assets	136		136		154
Deferred debits and other assets
Investment in consolidated subsidiaries	14,096		14,096		14,316
Regulatory assets	0		0		0
Goodwill	0		0		0
Nuclear decommissioning trust funds	0		0		0
Other assets and deferred debits	141		141		75
Total deferred debits and other assets	14,237		14,237		14,391
Total assets	14,373		14,373		14,545
Equity
Common stock equity	10,046		10,046		10,023
Noncontrolling interests	0		0		0
Total equity	10,046		10,046		10,023
Preferred stock of subsidiaries	0		0		0
Long-term debt, affiliate	0		0		0
Long-term debt, net	3,543		3,543		3,989
Total capitalization	13,589		13,589		14,012
Current liabilities
Current portion of long-term debt	450		450		205
Short-term debt	49		49		0
Notes payable to affiliated companies	0		0		0
Derivative liabilities	9		9		18
Other current liabilities	250		250		278
Total current liabilities	758		758		501
Deferred credits and other liabilities
Noncurrent income tax liabilities	0		0		3
Regulatory liabilities	0		0		0
Other liabilities and deferred credits	26		26		29
Total deferred credits and other liabilities	26		26		32
Total capitalization and liabilities	14,373		14,373		14,545
Condensed Consolidating Statement of Cash Flows
Net cash provided (used) by operating activities			477	54
Investing activities
Gross property additions			0	0
Nuclear fuel additions			0	0
Proceeds from sales of assets to affiliated companies				0
Purchases of available-for-sale securities and other investments			0	0
Proceeds from available-for-sale securities and other investments			0	0
Changes in advances to affiliated companies			(80)	(103)
Return of investment in consolidated subsidiaries			0	54
Contributions to consolidated subsidiaries			(10)	(56)
Other investing activities			0	0
Net cash provided (used) by investing activities			(90)	(105)
Financing activities
Issuance of common stock, net			26	405
Dividends paid on common stock			(366)	(354)
Dividends paid to parent			0	0
Dividends paid to parent in excess of retained earnings			0	0
Payments of short-term debt with original maturities greater than 90 days				0
Net increase (decrease) in short-term debt			49	(140)
Proceeds from issuance of long-term debt, net			494	0
Retirement of long-term debt			(700)	(100)
Changes in advances from affiliated companies			0	0
Contributions from parent			0	0
Other financing activities			0	0
Net cash provided (used) by financing activities			(497)	(189)
Net increase (decrease) in cash and cash equivalents			(110)	(240)
Cash and cash equivalents at beginning of period			110	606
Cash and cash equivalents at end of period	0	366	0	366
Subsidiary Guarantor
Operating revenues
Operating revenues	1,196	1,255	2,230	2,527
Affiliate revenues	0	0	0	0
Total operating revenues	1,196	1,255	2,230	2,527
Operating expenses
Fuel used in electric generation	348	368	703	781
Purchased power	256	239	409	452
Operation and maintenance	223	208	434	413
Depreciation, amortization and accretion	48	110	73	234
Taxes other than on income	83	83	168	176
Other	2	3	(8)	5
Total operating expenses	960	1,011	1,779	2,061
Operating (loss) income	236	244	451	466
Other income (expense)
Interest income	0	0	1	0
Allowance for equity funds used during construction	8	10	17	18
Other, net	1	0	6	3
Total other income (expense), net	9	10	24	21
Interest charges
Interest charges	73	75	148	145
Allowance for borrowed funds used during construction	(3)	(2)	(7)	(7)
Total interest charges, net	70	73	141	138
(Loss) income from continuing operations before income tax and equity in earnings of consolidated subsidiaries	175	181	334	349
Income tax (benefit) expense	64	67	124	136
Equity in earnings of consolidated subsidiaries	0	0	0	0
Income from continuing operations before cumulative effect of change in accounting principle	111	114	210	213
Discontinued operations, net of tax	(2)	0	(3)	1
Cumulative effect of change in accounting principle, net of tax	0		0	0
Net income (loss)	109	114	207	214
Net (income) loss attributable to noncontrolling interests, net of tax	(1)	(1)	(2)	(2)
Net income attributable to controlling interests	108	113	205	212
ASSETS
Utility plant, net	10,294		10,294		10,189
Current assets
Cash and cash equivalents	33	115	33	115
Receivables, net	556		556		497
Notes receivable from affiliated companies	27		27		48
Regulatory assets	137		137		105
Derivative collateral posted	104		104		140
Income taxes receivable	0		0		0
Prepayments and other current assets	769		769		751
Total current assets	1,626		1,626		1,811
Deferred debits and other assets
Investment in consolidated subsidiaries	0		0		0
Regulatory assets	1,266		1,266		1,387
Goodwill	0		0		0
Nuclear decommissioning trust funds	589		589		554
Other assets and deferred debits	236		236		238
Total deferred debits and other assets	2,091		2,091		2,179
Total assets	14,011		14,011		14,179
Equity
Common stock equity	4,769		4,769		4,957
Noncontrolling interests	3		3		4
Total equity	4,772		4,772		4,961
Preferred stock of subsidiaries	34		34		34
Long-term debt, affiliate	309		309		309
Long-term debt, net	4,182		4,182		4,182
Total capitalization	9,297		9,297		9,486
Current liabilities
Current portion of long-term debt	300		300		300
Short-term debt	67		67		0
Notes payable to affiliated companies	191		191		175
Derivative liabilities	160		160		188
Other current liabilities	1,057		1,057		1,002
Total current liabilities	1,775		1,775		1,665
Deferred credits and other liabilities
Noncurrent income tax liabilities	653		653		528
Regulatory liabilities	953		953		1,084
Other liabilities and deferred credits	1,333		1,333		1,416
Total deferred credits and other liabilities	2,939		2,939		3,028
Total capitalization and liabilities	14,011		14,011		14,179
Condensed Consolidating Statement of Cash Flows
Net cash provided (used) by operating activities			413	582
Investing activities
Gross property additions			(419)	(543)
Nuclear fuel additions			(13)	(13)
Proceeds from sales of assets to affiliated companies				0
Purchases of available-for-sale securities and other investments			(3,093)	(3,507)
Proceeds from available-for-sale securities and other investments			3,095	3,509
Changes in advances to affiliated companies			22	(5)
Return of investment in consolidated subsidiaries			0	0
Contributions to consolidated subsidiaries			0	0
Other investing activities			74	14
Net cash provided (used) by investing activities			(334)	(545)
Financing activities
Issuance of common stock, net			0	0
Dividends paid on common stock			0	0
Dividends paid to parent			(403)	(102)
Dividends paid to parent in excess of retained earnings			0	0
Payments of short-term debt with original maturities greater than 90 days				0
Net increase (decrease) in short-term debt			67	0
Proceeds from issuance of long-term debt, net			0	591
Retirement of long-term debt			0	(300)
Changes in advances from affiliated companies			16	(210)
Contributions from parent			10	33
Other financing activities			(6)	(6)
Net cash provided (used) by financing activities			(316)	6
Net increase (decrease) in cash and cash equivalents			(237)	43
Cash and cash equivalents at beginning of period			270	72
Cash and cash equivalents at end of period	33	115	33	115
Non-Guarantor Subsidiaries
Operating revenues
Operating revenues	1,060	1,117	2,193	2,380
Affiliate revenues	61	52	135	113
Total operating revenues	1,121	1,169	2,328	2,493
Operating expenses
Fuel used in electric generation	326	375	689	858
Purchased power	73	76	140	126
Operation and maintenance	343	347	694	676
Depreciation, amortization and accretion	131	123	260	245
Taxes other than on income	51	51	110	115
Other	0	0	0	0
Total operating expenses	924	972	1,893	2,020
Operating (loss) income	197	197	435	473
Other income (expense)
Interest income	0	2	0	3
Allowance for equity funds used during construction	18	15	38	28
Other, net	0	3	(2)	(4)
Total other income (expense), net	18	20	36	27
Interest charges
Interest charges	53	54	104	106
Allowance for borrowed funds used during construction	(6)	(5)	(11)	(9)
Total interest charges, net	47	49	93	97
(Loss) income from continuing operations before income tax and equity in earnings of consolidated subsidiaries	168	168	378	403
Income tax (benefit) expense	60	57	140	154
Equity in earnings of consolidated subsidiaries	0	0	0	0
Income from continuing operations before cumulative effect of change in accounting principle	108	111	238	249
Discontinued operations, net of tax	0	(1)	(1)	(1)
Cumulative effect of change in accounting principle, net of tax	0		0	(2)
Net income (loss)	108	110	237	246
Net (income) loss attributable to noncontrolling interests, net of tax	0	1	0	3
Net income attributable to controlling interests	108	111	237	249
ASSETS
Utility plant, net	11,367		11,367		10,961
Current assets
Cash and cash equivalents	19	209	19	209
Receivables, net	485		485		536
Notes receivable from affiliated companies	75		75		115
Regulatory assets	61		61		71
Derivative collateral posted	18		18		24
Income taxes receivable	0		0		0
Prepayments and other current assets	982		982		984
Total current assets	1,640		1,640		1,961
Deferred debits and other assets
Investment in consolidated subsidiaries	0		0		0
Regulatory assets	1,002		1,002		987
Goodwill	0		0		0
Nuclear decommissioning trust funds	1,097		1,097		1,017
Other assets and deferred debits	896		896		894
Total deferred debits and other assets	2,995		2,995		2,898
Total assets	16,002		16,002		15,820
Equity
Common stock equity	5,654		5,654		5,686
Noncontrolling interests	0		0		0
Total equity	5,654		5,654		5,686
Preferred stock of subsidiaries	59		59		59
Long-term debt, affiliate	0		0		0
Long-term debt, net	3,693		3,693		3,693
Total capitalization	9,406		9,406		9,438
Current liabilities
Current portion of long-term debt	0		0		0
Short-term debt	198		198		0
Notes payable to affiliated companies	5		5		3
Derivative liabilities	45		45		53
Other current liabilities	1,059		1,059		1,184
Total current liabilities	1,307		1,307		1,240
Deferred credits and other liabilities
Noncurrent income tax liabilities	1,754		1,754		1,608
Regulatory liabilities	1,544		1,544		1,461
Other liabilities and deferred credits	1,991		1,991		2,073
Total deferred credits and other liabilities	5,289		5,289		5,142
Total capitalization and liabilities	16,002		16,002		15,820
Condensed Consolidating Statement of Cash Flows
Net cash provided (used) by operating activities			567	694
Investing activities
Gross property additions			(585)	(598)
Nuclear fuel additions			(80)	(106)
Proceeds from sales of assets to affiliated companies				0
Purchases of available-for-sale securities and other investments			(294)	(308)
Proceeds from available-for-sale securities and other investments			269	283
Changes in advances to affiliated companies			40	294
Return of investment in consolidated subsidiaries			0	0
Contributions to consolidated subsidiaries			0	0
Other investing activities			8	0
Net cash provided (used) by investing activities			(642)	(435)
Financing activities
Issuance of common stock, net			0	0
Dividends paid on common stock			0	0
Dividends paid to parent			(275)	(50)
Dividends paid to parent in excess of retained earnings			0	(54)
Payments of short-term debt with original maturities greater than 90 days				0
Net increase (decrease) in short-term debt			198	0
Proceeds from issuance of long-term debt, net			0	0
Retirement of long-term debt			0	0
Changes in advances from affiliated companies			3	24
Contributions from parent			0	37
Other financing activities			(63)	(54)
Net cash provided (used) by financing activities			(137)	(97)
Net increase (decrease) in cash and cash equivalents			(212)	162
Cash and cash equivalents at beginning of period			231	47
Cash and cash equivalents at end of period	19	209	19	209
Other
Operating revenues
Operating revenues	0	0	0	0
Affiliate revenues	(61)	(52)	(135)	(113)
Total operating revenues	(61)	(52)	(135)	(113)
Operating expenses
Fuel used in electric generation	0	0	0	0
Purchased power	0	0	0	0
Operation and maintenance	(57)	(50)	(128)	(107)
Depreciation, amortization and accretion	0	0	0	0
Taxes other than on income	0	(1)	(4)	(4)
Other	0	0	0	0
Total operating expenses	(57)	(51)	(132)	(111)
Operating (loss) income	(4)	(1)	(3)	(2)
Other income (expense)
Interest income	0	(3)	0	(4)
Allowance for equity funds used during construction	0	0	0	0
Other, net	2	2	2	2
Total other income (expense), net	2	(1)	2	(2)
Interest charges
Interest charges	0	(2)	0	(4)
Allowance for borrowed funds used during construction	0	0	0	0
Total interest charges, net	0	(2)	0	(4)
(Loss) income from continuing operations before income tax and equity in earnings of consolidated subsidiaries	(2)	0	(1)	0
Income tax (benefit) expense	1	2	(1)	5
Equity in earnings of consolidated subsidiaries	(212)	(222)	(441)	(455)
Income from continuing operations before cumulative effect of change in accounting principle	(215)	(224)	(441)	(460)
Discontinued operations, net of tax	0	0	0	0
Cumulative effect of change in accounting principle, net of tax	0		0	0
Net income (loss)	(215)	(224)	(441)	(460)
Net (income) loss attributable to noncontrolling interests, net of tax	(1)	0	(1)	(1)
Net income attributable to controlling interests	(216)	(224)	(442)	(461)
ASSETS
Utility plant, net	88		88		90
Current assets
Cash and cash equivalents	0	0	0	0
Receivables, net	0		0		0
Notes receivable from affiliated companies	(196)		(196)		(177)
Regulatory assets	0		0		0
Derivative collateral posted	0		0		0
Income taxes receivable	0		0		0
Prepayments and other current assets	(190)		(190)		(273)
Total current assets	(386)		(386)		(450)
Deferred debits and other assets
Investment in consolidated subsidiaries	(14,096)		(14,096)		(14,316)
Regulatory assets	0		0		0
Goodwill	3,655		3,655		3,655
Nuclear decommissioning trust funds	0		0		0
Other assets and deferred debits	(527)		(527)		(469)
Total deferred debits and other assets	(10,968)		(10,968)		(11,130)
Total assets	(11,266)		(11,266)		(11,490)
Equity
Common stock equity	(10,423)		(10,423)		(10,643)
Noncontrolling interests	0		0		0
Total equity	(10,423)		(10,423)		(10,643)
Preferred stock of subsidiaries	0		0		0
Long-term debt, affiliate	(36)		(36)		(36)
Long-term debt, net	0		0		0
Total capitalization	(10,459)		(10,459)		(10,679)
Current liabilities
Current portion of long-term debt	0		0		0
Short-term debt	0		0		0
Notes payable to affiliated companies	(196)		(196)		(178)
Derivative liabilities	0		0		0
Other current liabilities	(187)		(187)		(273)
Total current liabilities	(383)		(383)		(451)
Deferred credits and other liabilities
Noncurrent income tax liabilities	(505)		(505)		(443)
Regulatory liabilities	88		88		90
Other liabilities and deferred credits	(7)		(7)		(7)
Total deferred credits and other liabilities	(424)		(424)		(360)
Total capitalization and liabilities	(11,266)		(11,266)		(11,490)
Condensed Consolidating Statement of Cash Flows
Net cash provided (used) by operating activities			(677)	(171)
Investing activities
Gross property additions			0	25
Nuclear fuel additions			0	0
Proceeds from sales of assets to affiliated companies				0
Purchases of available-for-sale securities and other investments			0	0
Proceeds from available-for-sale securities and other investments			0	0
Changes in advances to affiliated companies			18	(186)
Return of investment in consolidated subsidiaries			0	(54)
Contributions to consolidated subsidiaries			10	56
Other investing activities			0	0
Net cash provided (used) by investing activities			28	(159)
Financing activities
Issuance of common stock, net			0	0
Dividends paid on common stock			0	0
Dividends paid to parent			678	152
Dividends paid to parent in excess of retained earnings			0	54
Payments of short-term debt with original maturities greater than 90 days				0
Net increase (decrease) in short-term debt			0	0
Proceeds from issuance of long-term debt, net			0	0
Retirement of long-term debt			0	0
Changes in advances from affiliated companies			(19)	186
Contributions from parent			(10)	(70)
Other financing activities			0	8
Net cash provided (used) by financing activities			649	330
Net increase (decrease) in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	$ 0	$ 0	$ 0	$ 0