Fair Value (Tables)

3 Months Ended

Mar. 31, 2013

Fair Value Disclosures [Abstract]

Assets and liabilities measured and recorded at fair value on a recurring basis [Table Text Block]

	March 31, 2013								December 31, 2012
	Level 1		Level 2		Level 3		Net Balance		Level 1		Level 2		Level 3		Net Balance
	(In millions)
Assets:
Cash equivalents (a)	$	—	$	59	$	—	$	59	$	—	$	116	$	—	$	116
Nuclear decommissioning trusts	743		340		—		1,083		694		343		—		1,037
Other investments (b)	68		48		—		116		64		44		—		108
Derivative assets — FTRs	—		—		1		1		—		—		1		1
Total	$	811	$	447	$	1	$	1,259	$	758	$	503	$	1	$	1,262
Assets:
Current	$	—	$	59	$	1	$	60	$	—	$	116	$	1	$	117
Noncurrent	811		388		—		1,199		758		387		—		1,145
Total Assets	$	811	$	447	$	1	$	1,259	$	758	$	503	$	1	$	1,262

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

The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for the three months ended March 31, 2013 and 2012:

	Three Months Ended March 31,
	2013			2012
	(In millions)
Net Assets as of January 1	$	1		1
Change in fair value recorded in regulatory assets/liabilities	1			1
Purchases, issuances and settlements:
Settlements	(1		)	(2		)
Net Assets as of March 31	$	1		$	—
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 March 31, 2013 and March 31, 2012	$	1		$	—

Fair Value of Financial Instruments [Table Text Block]

The following table presents the carrying amount and fair value of financial instruments as of March 31, 2013 and December 31, 2012:

	March 31, 2013								December 31, 2012
	Carrying		Fair Value						Carrying		Fair Value
	Amount		Level 1		Level 2		Level 3		Amount		Level 1		Level 2		Level 3
	(In millions)
Notes receivable, excluding capital leases	$	5	$	—	$	—	$	5	$	5	$	—	$	—	$	5
Short-term borrowings — affiliates	51		—		—		51		80		—		—		80
Short-term borrowings — other	—		—		—		—		130		—		130		—
Long-term debt	5,197		—		5,111		711		4,963		—		5,021		620

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

The following table summarizes the fair value of the nuclear decommissioning trust fund assets:

	March 31		December 31
	2013		2012
	(In millions)
Fermi 2	$	1,066	$	1,021
Fermi 1	3		3
Low level radioactive waste	14		13
Total	$	1,083	$	1,037

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

The following table sets forth the gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds:

	Three Months Ended March 31,
	2013			2012
	(In millions)
Realized gains	$	8		$	6
Realized losses	$	(7	)	$	(4	)
Proceeds from sales of securities	$	12		$	11

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

The following table sets forth the fair value and unrealized gains for the nuclear decommissioning trust funds:

	March 31, 2013				December 31, 2012
	Fair		Unrealized		Fair		Unrealized
	Value		Gains		Value		Gains
	(In millions)
Equity securities	$	674	$	158	$	631	$	122
Debt securities	400		24		399		27
Cash and cash equivalents	9		—		7		—
	$	1,083	$	182	$	1,037	$	149