Regulatory Matters Regulatory Matters (Regulatory Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Regulatory Liabilities [Line Items]
Regulatory Liabilities	$ 664	$ 549
Regulatory Liability, Current	(278)	(66)
Regulatory Liability, Noncurrent	386	483
Renewable Energy [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	277	230
Refundable Revenue Decoupling/ Deferred Gain [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	127	127
Over Recovery of Securitization [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	72	54
Accrued PSCR refund [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	53	0
Refundable postretirement costs [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	48	0
Asset Removal Costs [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	33	81
Fermi 2 Refueling Outage [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	26	12
Energy Optimization [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	25	26
Refundable Uncollectible Expense [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	0	10
Other Liabilities [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	$ 3	$ 9