Fair Value (Tables)

9 Months Ended

Sep. 30, 2012

Fair Value Disclosures [Abstract]

Assets and liabilities measured and recorded at fair value on a recurring basis

The following table presents assets and liabilities measured and recorded at fair value on a recurring basis as of September 30, 2012 and December 31, 2011 (in millions):

	September 30, 2012															December 31, 2011
	Level 1			Level 2			Level 3			Netting (a)			Net Balance			Level 1			Level 2			Level 3			Netting (a)			Net Balance
Assets:
Cash equivalents (c)	$	—		$	69		$	—		$	—		$	69		$	—		$	140		$	—		$	—		$	140
Nuclear decommissioning trusts	651			378			—			—			1,029			577			360			—			—			937
Other investments (b)(c)(d)	64			42			—			—			106			57			38			—			—			95
Derivative assets:
Foreign currency exchange contracts	—			1			—			(1		)	—			—			3			—			(3		)	—
Commodity Contracts:
Natural Gas	845			94			20			(918		)	41			1,926			78			20			(1,991		)	33
Electricity	—			273			158			(295		)	136			—			523			224			(490		)	257
Other	41			5			7			(44		)	9			23			2			6			(25		)	6
Total derivative assets	886			373			185			(1,258		)	186			1,949			606			250			(2,509		)	296
Total	$	1,601		$	862		$	185		$	(1,258	)	$	1,390		$	2,583		$	1,144		$	250		$	(2,509	)	$	1,468
Liabilities:
Derivative liabilities:
Foreign currency exchange contracts	$	—		$	(2	)	$	—		$	1		$	(1	)	$	—		$	(5	)	$	—		$	3		$	(2	)
Interest rate contracts	—			(1		)	—			—			(1		)	—			(1		)	—			—			(1		)
Commodity Contracts:
Natural Gas	(824		)	(87		)	(64		)	919			(56		)	(1,940		)	(126		)	(14		)	1,976			(104		)
Electricity	—			(285		)	(134		)	295			(124		)	—			(513		)	(192		)	565			(140		)
Other	(36		)	(1		)	(1		)	44			6			(19		)	(1		)	—			20			—
Total derivative liabilities	(860		)	(376		)	(199		)	1,259			(176		)	(1,959		)	(646		)	(206		)	2,564			(247		)
Total	$	(860	)	$	(376	)	$	(199	)	$	1,259		$	(176	)	$	(1,959	)	$	(646	)	$	(206	)	$	2,564		$	(247	)
Net Assets (Liabilities) at the end of the period	$	741		$	486		$	(14	)	$	1		$	1,214		$	624		$	498		$	44		$	55		$	1,221
Assets:
Current	$	698		$	387		$	145		$	(1,038	)	$	192		$	1,571		$	660		$	181		$	(2,050	)	$	362
Noncurrent (e)	903			475			40			(220		)	1,198			1,012			484			69			(459		)	1,106
Total Assets	$	1,601		$	862		$	185		$	(1,258	)	$	1,390		$	2,583		$	1,144		$	250		$	(2,509	)	$	1,468
Liabilities:
Current	$	(696	)	$	(324	)	$	(165	)	$	1,039		$	(146	)	$	(1,603	)	$	(527	)	$	(152	)	$	2,124		$	(158	)
Noncurrent	(164		)	(52		)	(34		)	220			(30		)	(356		)	(119		)	(54		)	440			(89		)
Total Liabilities	$	(860	)	$	(376	)	$	(199	)	$	1,259		$	(176	)	$	(1,959	)	$	(646	)	$	(206	)	$	2,564		$	(247	)
Net Assets (Liabilities) at the end of the period	$	741		$	486		$	(14	)	$	1		$	1,214		$	624		$	498		$	44		$	55		$	1,221

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

The following tables present the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for the three and nine months ended September 30, 2012 and 2011 (in millions):

	Three Months Ended												Three Months Ended
	September 30, 2012												September 30, 2011
	Natural Gas			Electricity			Other			Total			Natural Gas			Electricity			Other		Total
Net Assets at the beginning of the period	$	2		$	50		$	5		$	57		$	1		$	57		$	7	$	65
Transfers into Level 3	—			—			—			—			(1		)	(6		)	—		(7		)
Transfers out of Level 3	—			—			—			—			—			(42		)	—		(42		)
Total gains:
Included in earnings	(43		)	12			1			(30		)	6			23			—		29
Recorded in regulatory assets/liabilities	—			—			7			7			—			—			—		—
Purchases, issuances and settlements:
Purchases	—			—			—			—			—			—			—		—
Settlements	(3		)	(38		)	(7		)	(48		)	(1		)	(35		)	—		(36		)
Net Assets (Liabilities) at the end of the period	$	(44	)	$	24		$	6		$	(14	)	$	5		$	(3	)	$	7	$	9
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30, 2012 and 2011 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$	(43	)	$	5		$	1		$	(37	)	$	6		$	5		$	—	$	11

	Nine Months Ended													Nine Months Ended
	September 30, 2012													September 30, 2011
	Natural Gas			Electricity			Other				Total			Natural Gas		Electricity			Other			Total
Net Assets at the beginning of the period	$	6		$	32		$	6			$	44		$	1	$	54		$	4		$	59
Transfers into Level 3	1			28			—				29			—		(4		)	—			(4		)
Transfers out of Level 3	(2		)	—			—				(2		)	1		(25		)	—			(24		)
Total gains:
Included in earnings	(38		)	53			—				15			3		34			2			39
Recorded in regulatory assets/liabilities	—			—			12				12			—		—			3			3
Purchases, issuances and settlements:
Purchases	—			1			—			—	1			—		1			—			1
Settlements	(11		)	(90		)	(12		)	—	(113		)	—		(63		)	(2		)	(65		)
Net Assets (Liabilities) at the end of the period	$	(44	)	$	24		$	6			$	(14	)	$	5	$	(3	)	$	7		$	9
The amount of total gains (losses) included in net income attributed to the change in unrealized gains (losses) related to assets and liabilities held at September 30, 2012 and 2011 and reflected in Operating revenues and Fuel, purchased power and gas in the Consolidated Statements of Operations	$	(39	)	$	43		$	—			$	4		$	5	$	17		$	2		$	24

Transfers Between Level 1 Level 2 and Level 3 [Table Text Block]

The following table shows transfers between the levels of the fair value hierarchy for the three and nine months ended September

30, 2012 and 2011 (in millions):

	Three Months Ended						Three Months Ended
	September 30, 2012						September 30, 2011
	Level 1		Level 2		Level 3		Level 1		Level 2			Level 3
Transfers into Level 1 from	N/A		$	—	$	—	N/A		$	—		$	—
Transfers into Level 2 from	$	—	N/A		—		$	—	N/A			42
Transfers into Level 3 from	—		—		N/A		—		(7		)	N/A

	Nine Months Ended						Nine Months Ended
	September 30, 2012						September 30, 2011
	Level 1		Level 2		Level 3		Level 1		Level 2			Level 3
Transfers into Level 1 from	N/A		$	—	$	—	N/A		$	—		$	—
Transfers into Level 2 from	$	—	N/A		2		$	—	N/A			24
Transfers into Level 3 from	—		29		N/A		—		(4		)	N/A

Quantitative Disclosure of Unobservable Inputs [Table Text Block]

	September 30, 2012
Commodity Contracts	Derivative Assets		Derivative Liabilities			Valuation Techniques	Unobservable Input	Range
Natural Gas	$	20	$	(64	)	Discounted Cash Flow	Forward basis price (per MMBtu)	$	(0.63	)	—	$	1.90	/MMBtu
Electricity	158		(134		)	Discounted Cash Flow	Forward market price (per Mwh)	21			—	32		/Mwh
							Forward basis price (per Mwh)	(1		)	—	15		/Mwh

Fair Value of Financial Instruments [Table Text Block]

:

	September 30, 2012								December 31, 2011
	Carrying		Fair Value						Carrying		Fair
	Amount		Level 1		Level 2		Level 3		Amount		Value
Notes receivable, excluding capital leases	$	42	$	—	$	—	$	42	$	48	$	48
Dividends payable	107		107		—		—		99		99
Short-term borrowings	98		—		98		—		419		419
Long-term debt	7,735		314		7,998		612		7,682		8,757

Fair Value of Nuclear Decommissioning Trust Fund Assets Text Block [Table]

:

	September 30, 2012		December 31, 2011
Fermi 2	$	1,003	$	915
Fermi 1	3		3
Low level radioactive waste	23		19
Total	$	1,029	$	937

Schedule of Realized Gain (Loss) [Table Text Block]

:

	Three Months Ended						Nine Months Ended
	September 30						September 30
	2012			2011			2012			2011
Realized gains	$	7		$	8		$	21		$	34
Realized losses	(6		)	(9		)	(17		)	(26		)
Proceeds from sales of securities	12			10			48			69

Fair Value and Unrealized Gains for Nuclear Decommissioning Trust Fund Table [Table] [Table Text Block]

:

	September 30, 2012				December 31, 2011
	Fair Value		Unrealized Gains		Fair Value		Unrealized Gains
Equity securities	$	615	$	124	$	533	$	80
Debt securities	405		29		385		22
Cash and cash equivalents	9		—		19		—
	$	1,029	$	153	$	937	$	102