Fair Value Measurements (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010		Dec. 31, 2010
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	$ 16,635,000,000				$ 16,635,000,000				$ 16,811,000,000
Long Term Debt, Fair Value	18,251,000,000				18,251,000,000				18,285,000,000
Other Temporary Investments
Estimated Fair Value	311,000,000				311,000,000				416,000,000
Debt And Equity Securities Within Other Temporary Investments [Abstract]
Proceeds From Investment Sales	51,000,000		16,000,000		247,000,000		257,000,000
Purchases of Investments	5,000,000		24,000,000		153,000,000		221,000,000
Gross Realized Gains on Investment Sales	0		16,000,000		0		16,000,000
Gross Realized Losses on Investment Sales	0		0		0		0
Nuclear trust fund investments
Estimated Fair Value	1,574,000,000				1,574,000,000				1,515,000,000
Gross Unrealized Gains	262,000,000				262,000,000				209,000,000
Other-Than-Temporary Impairments	(108,000,000)				(108,000,000)				(126,000,000)
Securities activity within the decommissioning and SNF trusts
Proceeds from Investment Sales	177,000,000		360,000,000		465,000,000		592,000,000
Purchases of Investments	186,000,000		369,000,000		492,000,000		617,000,000
Gross Realized Gains on Investment Sales	7,000,000		1,000,000		12,000,000		6,000,000
Gross Realized Losses on Investment Sales	4,000,000		0		9,000,000		0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	1,574,000,000				1,574,000,000				1,515,000,000
Assets:
Cash and Cash Equivalents	417,000,000	[1]			417,000,000	[1]			294,000,000	[1]
Total Other Temporary Investments	311,000,000				311,000,000				416,000,000
Risk Management Assets
Risk Management Assets	516,000,000				516,000,000				642,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	1,574,000,000				1,574,000,000				1,515,000,000
Total Assets	2,818,000,000				2,818,000,000				2,867,000,000
Liabilities:
Risk Management Liabilities	218,000,000				218,000,000				270,000,000
Changes in the fair value of net trading derivatives and other investments
Beginning Balance	73,000,000		116,000,000		85,000,000		62,000,000
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets)	(10,000,000)	[2],[3]	(25,000,000)	[2],[3]	(9,000,000)	[2],[3]	4,000,000	[2],[3]
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date	10,000,000	[2]	10,000,000	[2]	7,000,000	[2]	33,000,000	[2]
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income	0		0		0		0
Purchases, Issuances and Settlements	14,000,000	[4]	14,000,000	[4]	6,000,000	[4]	(13,000,000)	[4]
Transfers into Level 3	3,000,000	[5],[6]	1,000,000	[5],[6]	4,000,000	[5],[6]	12,000,000	[5],[6]
Transfers out of Level 3	(4,000,000)	[6],[7]	(6,000,000)	[6],[7]	(12,000,000)	[6],[7]	(5,000,000)	[6],[7]
Changes in Fair Value Allocated to Regulated Jurisdiction	(9,000,000)	[8]	(10,000,000)	[8]	(4,000,000)	[8]	7,000,000	[8]
Ending Balance	77,000,000		100,000,000		77,000,000		100,000,000
Fair Value Measurements (Textuals) [Abstract]
Adjusted Cost of Debt Securities	848,000,000				848,000,000				835,000,000
Adjusted Cost of Domestic Equity Securities	447,000,000				447,000,000				451,000,000
Risk Management Commodity Contracts [Member]
Risk Management Assets
Risk Management Assets	450,000,000	[10],[9]			450,000,000	[10],[9]			551,000,000	[11],[9]
Liabilities:
Risk Management Liabilities	213,000,000	[10],[9]			213,000,000	[10],[9]			263,000,000	[11],[9]
Risk Management Commodity Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	17,000,000	[10],[9]			17,000,000	[10],[9]			20,000,000	[11],[9]
Liabilities:
Risk Management Liabilities	20,000,000	[10],[9]			20,000,000	[10],[9]			25,000,000	[11],[9]
Risk Management Commodity Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	1,006,000,000	[10],[9]			1,006,000,000	[10],[9]			1,432,000,000	[11],[9]
Liabilities:
Risk Management Liabilities	882,000,000	[10],[9]			882,000,000	[10],[9]			1,325,000,000	[11],[9]
Risk Management Commodity Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	113,000,000	[10],[9]			113,000,000	[10],[9]			112,000,000	[11],[9]
Liabilities:
Risk Management Liabilities	36,000,000	[10],[9]			36,000,000	[10],[9]			27,000,000	[11],[9]
Risk Management Commodity Contracts [Member] | Fair Value Inputs Other [Member]
Risk Management Assets
Risk Management Assets	(686,000,000)	[10],[9]			(686,000,000)	[10],[9]			(1,013,000,000)	[11],[9]
Liabilities:
Risk Management Liabilities	(725,000,000)	[10],[9]			(725,000,000)	[10],[9]			(1,114,000,000)	[11],[9]
Commodity Hedges [Member]
Risk Management Assets
Risk Management Assets	21,000,000	[9]			21,000,000	[9]			13,000,000	[9]
Liabilities:
Risk Management Liabilities	2,000,000	[9]			2,000,000	[9]			2,000,000	[9]
Commodity Hedges [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	8,000,000	[9]			8,000,000	[9]			11,000,000	[9]
Liabilities:
Risk Management Liabilities	2,000,000	[9]			2,000,000	[9]			4,000,000	[9]
Commodity Hedges [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	30,000,000	[9]			30,000,000	[9]			17,000,000	[9]
Liabilities:
Risk Management Liabilities	17,000,000	[9]			17,000,000	[9]			13,000,000	[9]
Commodity Hedges [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	0	[9]			0	[9]			0	[9]
Liabilities:
Risk Management Liabilities	0	[9]			0	[9]			0	[9]
Commodity Hedges [Member] | Fair Value Inputs Other [Member]
Risk Management Assets
Risk Management Assets	(17,000,000)	[9]			(17,000,000)	[9]			(15,000,000)	[9]
Liabilities:
Risk Management Liabilities	(17,000,000)	[9]			(17,000,000)	[9]			(15,000,000)	[9]
Interest Rate Foreign Currency Hedges [Member]
Risk Management Assets
Risk Management Assets	1,000,000				1,000,000				25,000,000
Liabilities:
Risk Management Liabilities	3,000,000				3,000,000				4,000,000
Interest Rate Foreign Currency Hedges [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	0				0				0
Liabilities:
Risk Management Liabilities	0				0				0
Interest Rate Foreign Currency Hedges [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	1,000,000				1,000,000				25,000,000
Liabilities:
Risk Management Liabilities	3,000,000				3,000,000				4,000,000
Interest Rate Foreign Currency Hedges [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	0				0				0
Liabilities:
Risk Management Liabilities	0				0				0
Interest Rate Foreign Currency Hedges [Member] | Fair Value Inputs Other [Member]
Risk Management Assets
Risk Management Assets	0				0				0
Liabilities:
Risk Management Liabilities	0				0				0
Fair Value Hedges [Member]
Risk Management Assets
Risk Management Assets	8,000,000				8,000,000				7,000,000
Liabilities:
Risk Management Liabilities									1,000,000
Fair Value Hedges [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	0				0				0
Liabilities:
Risk Management Liabilities									0
Fair Value Hedges [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	8,000,000				8,000,000				7,000,000
Liabilities:
Risk Management Liabilities									1,000,000
Fair Value Hedges [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	0				0				0
Liabilities:
Risk Management Liabilities									0
Fair Value Hedges [Member] | Fair Value Inputs Other [Member]
Risk Management Assets
Risk Management Assets	0				0				0
Liabilities:
Risk Management Liabilities									0
2011 [Member] | Level 1 [Member]
Fair Value Measurements (Textuals) [Abstract]
Maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities)	(1,000,000)				(1,000,000)				(2,000,000)
2011 [Member] | Level 2 [Member]
Fair Value Measurements (Textuals) [Abstract]
Maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities)	13,000,000				13,000,000				13,000,000
2011 [Member] | Level 3 [Member]
Fair Value Measurements (Textuals) [Abstract]
Maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities)	11,000,000				11,000,000				18,000,000
2012 - 2014 [Member] | Level 1 [Member]
Fair Value Measurements (Textuals) [Abstract]
Maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities)	3,000,000				3,000,000				2,000,000
2012 - 2014 [Member] | Level 2 [Member]
Fair Value Measurements (Textuals) [Abstract]
Maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities)	75,000,000				75,000,000				66,000,000
2012 - 2014 [Member] | Level 3 [Member]
Fair Value Measurements (Textuals) [Abstract]
Maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities)	25,000,000				25,000,000				24,000,000
2015 - 2016 [Member] | Level 2 [Member]
Fair Value Measurements (Textuals) [Abstract]
Maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities)	18,000,000				18,000,000				12,000,000
2015 - 2016 [Member] | Level 3 [Member]
Fair Value Measurements (Textuals) [Abstract]
Maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities)	15,000,000				15,000,000				16,000,000
2015 - 2018 [Member] | Level 1 [Member]
Fair Value Measurements (Textuals) [Abstract]
Maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities)	(5,000,000)				(5,000,000)				(5,000,000)
2017 - 2028 [Member] | Level 2 [Member]
Fair Value Measurements (Textuals) [Abstract]
Maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities)	18,000,000				18,000,000				16,000,000
2017 - 2028 [Member] | Level 3 [Member]
Fair Value Measurements (Textuals) [Abstract]
Maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities)	26,000,000				26,000,000				27,000,000
Within 1 Year [Member]
Nuclear trust fund investments
Estimated Fair Value	77,000,000				77,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	77,000,000				77,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	77,000,000				77,000,000
1 year - 5 years [Member]
Nuclear trust fund investments
Estimated Fair Value	256,000,000				256,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	256,000,000				256,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	256,000,000				256,000,000
5 years - 10 years [Member]
Nuclear trust fund investments
Estimated Fair Value	281,000,000				281,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	281,000,000				281,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	281,000,000				281,000,000
After 10 years [Member]
Nuclear trust fund investments
Estimated Fair Value	265,000,000				265,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	265,000,000				265,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	265,000,000				265,000,000
Cash [Member]
Other Temporary Investments
Cost	212,000,000	[12]			212,000,000	[12]			225,000,000	[12]
Gross Unrealized Gains	0				0				0
Gross Unrealized Losses	0				0				0
Assets:
Total Other Temporary Investments	212,000,000	[1]			212,000,000	[1]			225,000,000	[1]
Cash [Member] | Level 1 [Member]
Assets:
Total Other Temporary Investments	160,000,000	[1]			160,000,000	[1]			184,000,000	[1]
Cash [Member] | Level 2 [Member]
Assets:
Total Other Temporary Investments	0	[1]			0	[1]			0	[1]
Cash [Member] | Level 3 [Member]
Assets:
Total Other Temporary Investments	0	[1]			0	[1]			0	[1]
Cash [Member] | Fair Value Inputs Other [Member]
Assets:
Total Other Temporary Investments	52,000,000	[1]			52,000,000	[1]			41,000,000	[1]
Fixed Income Funds [Member]
Nuclear trust fund investments
Gross Unrealized Gains	31,000,000				31,000,000				26,000,000
Other-Than-Temporary Impairments	(3,000,000)				(3,000,000)				(3,000,000)
Mutual Funds Fixed Income [Member]
Other Temporary Investments
Cost	63,000,000				63,000,000				69,000,000
Gross Unrealized Gains	0				0				0
Gross Unrealized Losses	0				0				0
Assets:
Total Other Temporary Investments	63,000,000				63,000,000				69,000,000
Mutual Funds Fixed Income [Member] | Level 1 [Member]
Assets:
Total Other Temporary Investments	63,000,000				63,000,000				69,000,000
Mutual Funds Fixed Income [Member] | Level 2 [Member]
Assets:
Total Other Temporary Investments	0				0				0
Mutual Funds Fixed Income [Member] | Level 3 [Member]
Assets:
Total Other Temporary Investments	0				0				0
Mutual Funds Fixed Income [Member] | Fair Value Inputs Other [Member]
Assets:
Total Other Temporary Investments	0				0				0
Variable Rate Demand Notes [Member]
Other Temporary Investments
Cost	21,000,000				21,000,000				97,000,000
Gross Unrealized Gains	0				0				0
Gross Unrealized Losses	0				0				0
Assets:
Total Other Temporary Investments	21,000,000				21,000,000				97,000,000
Variable Rate Demand Notes [Member] | Level 1 [Member]
Assets:
Total Other Temporary Investments	0				0				0
Variable Rate Demand Notes [Member] | Level 2 [Member]
Assets:
Total Other Temporary Investments	21,000,000				21,000,000				97,000,000
Variable Rate Demand Notes [Member] | Level 3 [Member]
Assets:
Total Other Temporary Investments	0				0				0
Variable Rate Demand Notes [Member] | Fair Value Inputs Other [Member]
Assets:
Total Other Temporary Investments	0				0				0
Equity Securities - Domestic [Member]
Nuclear trust fund investments
Estimated Fair Value									634,000,000	[13]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities									634,000,000	[13]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts									634,000,000	[13]
Equity Securities - Domestic [Member] | Level 1 [Member]
Nuclear trust fund investments
Estimated Fair Value									634,000,000	[13]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities									634,000,000	[13]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts									634,000,000	[13]
Domestic [Member]
Nuclear trust fund investments
Estimated Fair Value	678,000,000	[13]			678,000,000	[13]
Gross Unrealized Gains	231,000,000				231,000,000				183,000,000
Other-Than-Temporary Impairments	(105,000,000)				(105,000,000)				(123,000,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	678,000,000	[13]			678,000,000	[13]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	678,000,000	[13]			678,000,000	[13]
Domestic [Member] | Level 1 [Member]
Nuclear trust fund investments
Estimated Fair Value	678,000,000	[13]			678,000,000	[13]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	678,000,000	[13]			678,000,000	[13]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	678,000,000	[13]			678,000,000	[13]
Domestic [Member] | Level 2 [Member]
Nuclear trust fund investments
Estimated Fair Value	0	[13]			0	[13]			0	[13]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0	[13]			0	[13]			0	[13]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0	[13]			0	[13]			0	[13]
Domestic [Member] | Level 3 [Member]
Nuclear trust fund investments
Estimated Fair Value	0	[13]			0	[13]			0	[13]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0	[13]			0	[13]			0	[13]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0	[13]			0	[13]			0	[13]
Domestic [Member] | Fair Value Inputs Other [Member]
Nuclear trust fund investments
Estimated Fair Value	0	[13]			0	[13]			0	[13]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0	[13]			0	[13]			0	[13]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0	[13]			0	[13]			0	[13]
Mutual Funds Equity [Member]
Other Temporary Investments
Cost	7,000,000				7,000,000				18,000,000
Gross Unrealized Gains	8,000,000				8,000,000				7,000,000
Gross Unrealized Losses	0				0				0
Assets:
Total Other Temporary Investments	15,000,000	[13]			15,000,000	[13]			25,000,000	[13]
Mutual Funds Equity [Member] | Level 1 [Member]
Assets:
Total Other Temporary Investments	15,000,000	[13]			15,000,000	[13]			25,000,000	[13]
Mutual Funds Equity [Member] | Level 2 [Member]
Assets:
Total Other Temporary Investments	0	[13]			0	[13]			0	[13]
Mutual Funds Equity [Member] | Level 3 [Member]
Assets:
Total Other Temporary Investments	0	[13]			0	[13]			0	[13]
Mutual Funds Equity [Member] | Fair Value Inputs Other [Member]
Assets:
Total Other Temporary Investments	0	[13]			0	[13]			0	[13]
Cash and Cash Equivalents [Member]
Nuclear trust fund investments
Estimated Fair Value	17,000,000	[14]			17,000,000	[14]			20,000,000	[14]
Gross Unrealized Gains	0				0				0
Other-Than-Temporary Impairments	0				0				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	17,000,000	[14]			17,000,000	[14]			20,000,000	[14]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	17,000,000	[14]			17,000,000	[14]			20,000,000	[14]
Cash and Cash Equivalents [Member] | Level 1 [Member]
Nuclear trust fund investments
Estimated Fair Value	0	[14]			0	[14]			0	[14]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0	[14]			0	[14]			0	[14]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0	[14]			0	[14]			0	[14]
Cash and Cash Equivalents [Member] | Level 2 [Member]
Nuclear trust fund investments
Estimated Fair Value	5,000,000	[14]			5,000,000	[14]			8,000,000	[14]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	5,000,000	[14]			5,000,000	[14]			8,000,000	[14]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	5,000,000	[14]			5,000,000	[14]			8,000,000	[14]
Cash and Cash Equivalents [Member] | Level 3 [Member]
Nuclear trust fund investments
Estimated Fair Value	0	[14]	0	[14]	0	[14]	0	[14]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0	[14]	0	[14]	0	[14]	0	[14]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0	[14]	0	[14]	0	[14]	0	[14]
Cash and Cash Equivalents [Member] | Fair Value Inputs Other [Member]
Nuclear trust fund investments
Estimated Fair Value	12,000,000	[14]			12,000,000	[14]			12,000,000	[14]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	12,000,000	[14]			12,000,000	[14]			12,000,000	[14]
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	12,000,000	[14]			12,000,000	[14]			12,000,000	[14]
US Government Agencies Debt Securities [Member]
Nuclear trust fund investments
Estimated Fair Value	484,000,000				484,000,000				461,000,000
Gross Unrealized Gains	27,000,000				27,000,000				23,000,000
Other-Than-Temporary Impairments	(1,000,000)				(1,000,000)				(1,000,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	484,000,000				484,000,000				461,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	484,000,000				484,000,000				461,000,000
US Government Agencies Debt Securities [Member] | Level 1 [Member]
Nuclear trust fund investments
Estimated Fair Value	0				0				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0				0				0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0				0				0
US Government Agencies Debt Securities [Member] | Level 2 [Member]
Nuclear trust fund investments
Estimated Fair Value	484,000,000				484,000,000				461,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	484,000,000				484,000,000				461,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	484,000,000				484,000,000				461,000,000
US Government Agencies Debt Securities [Member] | Level 3 [Member]
Nuclear trust fund investments
Estimated Fair Value	0				0				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0				0				0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0				0				0
US Government Agencies Debt Securities [Member] | Fair Value Inputs Other [Member]
Nuclear trust fund investments
Estimated Fair Value	0				0				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0				0				0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0				0				0
Corporate Debt [Member]
Nuclear trust fund investments
Estimated Fair Value	57,000,000				57,000,000				59,000,000
Gross Unrealized Gains	3,000,000				3,000,000				4,000,000
Other-Than-Temporary Impairments	(1,000,000)				(1,000,000)				(2,000,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	57,000,000				57,000,000				59,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	57,000,000				57,000,000				59,000,000
Corporate Debt [Member] | Level 1 [Member]
Nuclear trust fund investments
Estimated Fair Value	0				0				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0				0				0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0				0				0
Corporate Debt [Member] | Level 2 [Member]
Nuclear trust fund investments
Estimated Fair Value	57,000,000				57,000,000				59,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	57,000,000				57,000,000				59,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	57,000,000				57,000,000				59,000,000
Corporate Debt [Member] | Level 3 [Member]
Nuclear trust fund investments
Estimated Fair Value	0				0				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0				0				0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0				0				0
Corporate Debt [Member] | Fair Value Inputs Other [Member]
Nuclear trust fund investments
Estimated Fair Value	0				0				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0				0				0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0				0				0
State and Local Jurisdiction [Member]
Nuclear trust fund investments
Estimated Fair Value	338,000,000				338,000,000				341,000,000
Gross Unrealized Gains	1,000,000				1,000,000				(1,000,000)
Other-Than-Temporary Impairments	(1,000,000)				(1,000,000)				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	338,000,000				338,000,000				341,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	338,000,000				338,000,000				341,000,000
State and Local Jurisdiction [Member] | Level 1 [Member]
Nuclear trust fund investments
Estimated Fair Value	0				0				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0				0				0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0				0				0
State and Local Jurisdiction [Member] | Level 2 [Member]
Nuclear trust fund investments
Estimated Fair Value	338,000,000				338,000,000				341,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	338,000,000				338,000,000				341,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	338,000,000				338,000,000				341,000,000
State and Local Jurisdiction [Member] | Level 3 [Member]
Nuclear trust fund investments
Estimated Fair Value	0				0				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0				0				0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0				0				0
State and Local Jurisdiction [Member] | Fair Value Inputs Other [Member]
Nuclear trust fund investments
Estimated Fair Value	0				0				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0				0				0
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0				0				0
Dedesignated Risk Management Contracts [Member]
Risk Management Assets
Risk Management Assets	36,000,000	[15]			36,000,000	[15]			46,000,000	[15]
Dedesignated Risk Management Contracts [Member] | Level 1 [Member]
Risk Management Assets
Risk Management Assets	0	[15]			0	[15]			0	[15]
Dedesignated Risk Management Contracts [Member] | Level 2 [Member]
Risk Management Assets
Risk Management Assets	0	[15]			0	[15]			0	[15]
Dedesignated Risk Management Contracts [Member] | Level 3 [Member]
Risk Management Assets
Risk Management Assets	0	[15]			0	[15]			0	[15]
Dedesignated Risk Management Contracts [Member] | Fair Value Inputs Other [Member]
Risk Management Assets
Risk Management Assets	36,000,000	[15]			36,000,000	[15]			46,000,000	[15]
Other Temporary Investments [Member]
Other Temporary Investments
Cost	303,000,000				303,000,000				409,000,000
Gross Unrealized Gains	8,000,000				8,000,000				7,000,000
Gross Unrealized Losses	0				0				0
Level 1 [Member]
Nuclear trust fund investments
Estimated Fair Value	678,000,000				678,000,000				634,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	678,000,000				678,000,000				634,000,000
Assets:
Cash and Cash Equivalents	208,000,000	[1]			208,000,000	[1]			170,000,000	[1]
Total Other Temporary Investments	238,000,000				238,000,000				278,000,000
Risk Management Assets
Risk Management Assets	25,000,000				25,000,000				31,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	678,000,000				678,000,000				634,000,000
Total Assets	1,149,000,000				1,149,000,000				1,113,000,000
Liabilities:
Risk Management Liabilities	22,000,000				22,000,000				29,000,000
Level 2 [Member]
Nuclear trust fund investments
Estimated Fair Value	884,000,000				884,000,000				869,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	884,000,000				884,000,000				869,000,000
Assets:
Cash and Cash Equivalents	0	[1]			0	[1]			0	[1]
Total Other Temporary Investments	21,000,000				21,000,000				97,000,000
Risk Management Assets
Risk Management Assets	1,045,000,000				1,045,000,000				1,481,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	884,000,000				884,000,000				869,000,000
Total Assets	1,950,000,000				1,950,000,000				2,447,000,000
Liabilities:
Risk Management Liabilities	902,000,000				902,000,000				1,343,000,000
Level 3 [Member]
Nuclear trust fund investments
Estimated Fair Value	0				0				0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	0				0				0
Assets:
Cash and Cash Equivalents	0	[1]			0	[1]			0	[1]
Total Other Temporary Investments	0				0				0
Risk Management Assets
Risk Management Assets	113,000,000				113,000,000				112,000,000
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	0				0				0
Total Assets	113,000,000				113,000,000				112,000,000
Liabilities:
Risk Management Liabilities	36,000,000				36,000,000				27,000,000
Fair Value Inputs Other [Member]
Nuclear trust fund investments
Estimated Fair Value	12,000,000				12,000,000				12,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	12,000,000				12,000,000				12,000,000
Assets:
Cash and Cash Equivalents	209,000,000	[1]			209,000,000	[1]			124,000,000	[1]
Total Other Temporary Investments	52,000,000				52,000,000				41,000,000
Risk Management Assets
Risk Management Assets	(667,000,000)				(667,000,000)				(982,000,000)
Spent Nuclear Fuel and Decommissioning Trusts
Spent Nuclear Fuel and Decommissioning Trusts	12,000,000				12,000,000				12,000,000
Total Assets	(394,000,000)				(394,000,000)				(805,000,000)
Liabilities:
Risk Management Liabilities	$ (742,000,000)				$ (742,000,000)				$ (1,129,000,000)

[1] Amounts in ''Other'' column primarily represent cash deposits in bank accounts with financial institutions or with third parties. Level 1 amounts primarily represent investments in money market funds.

[2] Included in revenues on our Condensed Consolidated Statements of Income.

[3] Represents the change in fair value between the beginning of the reporting period and the settlement of the risk management commodity contract.

[4] Represents the settlement of risk management commodity contracts for the reporting period.

[5] Represents existing assets or liabilities that were previously categorized as Level 2.

[6] Transfers are recognized based on their value at the beginning of the reporting period that the transfer occurred.

[7] Represents existing assets or liabilities that were previously categorized as Level 3.

[8] Relates to the net gains (losses) of those contracts that are not reflected on our Condensed Consolidated Statements of Income. These net gains (losses) are recorded as regulatory liabilities/assets

[9] Amounts in ''Other'' column primarily represent counterparty netting of risk management and hedging contracts and associated cash collateral under the accounting guidance for ''Derivatives and Hedging.''

[10] The June 30, 2011 maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), is as follows: Level 1 matures ($1) million in 2011, $3 million in periods 2012-2014 and ($5) million in periods 2015-2018; Level 2 matures $13 million in 2011, $75 million in periods 2012-2014, $18 million in periods 2015-2016 and $18 million in periods 2017-2028; Level 3 matures $11 million in 2011, $25 million in periods 2012-2014, $15 million in periods 2015-2016 and $26 million in periods 2017-2028. Risk management commodity contracts are substantially comprised of power contracts.

[11] The December 31, 2010 maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), is as follows: Level 1 matures ($2) million in 2011, $2 million in periods 2012-2014 and ($5) million in periods 2015-2018; Level 2 matures $13 million in 2011, $66 million in periods 2012-2014, $12 million in periods 2015-2016 and $16 million in periods 2017-2028; Level 3 matures $18 million in 2011, $24 million in periods 2012-2014, $16 million in periods 2015-2016 and $27 million in periods 2017-2028. Risk management commodity contracts are substantially comprised of power contracts.

[12] Primarily represents amounts held for the repayment of debt.

[13] Amounts represent publicly traded equity securities and equity-based mutual funds.

[14] Amounts in ''Other'' column primarily represent accrued interest receivables from financial institutions. Level 2 amounts primarily represent investments in money market funds.

[15] Represents contracts that were originally MTM but were subsequently elected as normal under the accounting guidance for ''Derivatives and Hedging.'' At the time of the normal election, the MTM value was frozen and no longer fair valued. This MTM value will be amortized into revenues over the remaining life of the contracts.