CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows From Operating Activities
Net loss (income)	$ (641)	$ (909)	$ (1,079)
Adjustments to reconcile (loss) income to net cash provided by operating activities:
Non-cash reorganization items	48	23	0
Equity in income from unconsolidated affiliates	(45)	(46)	(85)
Distributions from unconsolidated affiliates	45	24	82
Mark to Market on Interest Rate Swaps	(6)	0	0
Depreciation and amortization	290	292	330
Deferred taxes and tax credits	(72)	162	(903)
Loss on disposal and asset impairments	464	117	1,738
Loss on early extinguishment of debt	3	0	0
Proceeds from U.S. Treasury Grants	0	44	388
Changes in operating assets and liabilities:
(Increase) decrease in margin and collateral deposits	(10)	(20)	14
(Increase) decrease in receivables	(5)	30	251
Decrease (increase) in inventory	61	(6)	(42)
(Increase) decrease in prepaid expenses and other	13	(9)	(9)
Decrease (increase) in restricted cash and cash equivalents	4	(2)	(4)
Decrease (increase) in rent payments in excess of levelized rent expense	45	(76)	(76)
Increase (decrease) in payables and other current liabilities	50	5	172
Decrease (increase) in derivative assets and liabilities	33	(26)	0
Decrease (increase) in other operating—assets	3	(2)	(73)
(Decrease) increase in other operating—liabilities	(47)	(68)	(44)
Operating cash flows from continuing operations	233	(467)	660
Operating cash flows from discontinued operations, net	(2)	(46)	(34)
Net cash provided by (used in) operating activities	231	(513)	626
Cash Flows From Financing Activities
Cash contributions from noncontrolling interests	94	288	0
Borrowings under short-term debt	4	195	32
Borrowings on long-term debt	171	79	481
Payments on debt	(123)	(56)	(107)
Borrowing held in escrow pending completion of project construction	0	97	(97)
Cash contribution from Edison International related to the tax-allocation agreements	12	0	0
Cash dividends to noncontrolling interests	(29)	(18)	0
Payments to affiliates related to stock-based awards	(14)	(17)	(8)
Excess tax benefits related to stock-based exercises	3	5	2
Financing costs	(6)	(9)	(26)
Net cash provided by financing activities from continuing operations	112	564	277
Cash Flows From Investing Activities
Capital expenditures	(92)	(355)	(672)
Proceeds from sale of assets	3	4	9
Proceeds from return of capital and loan repayments from unconsolidated affiliates	24	10	46
Proceeds from settlement of insurance claims	2	2	0
Cash settlement with turbine manufacturer	5	0	0
Purchase of interest of acquired companies	0	0	(3)
Investments in and loans to unconsolidated affiliates	(3)	0	(10)
Increase in restricted deposits and restricted cash and cash equivalents	0	(83)	(4)
Investment in other assets	4	(8)	(30)
Investing cash flows from continuing operations	(57)	(430)	(664)
Investing cash flows from discontinued operations, net	0	(31)	(14)
Net cash used in investing activities	(57)	(461)	(678)
Net (decrease) increase in cash and cash equivalents from continuing operations	288	(333)	273
Cash and cash equivalents at beginning of period from continuing operations	888	1,221	948
Cash and cash equivalents at end of period from continuing operations	1,176	888	1,221
Net (decrease) increase in cash and cash equivalents from discontinued operations	(2)	(77)	(48)
Cash and cash equivalents at beginning of period from discontinued operations	2	79	127
Cash and cash equivalents at end of period from discontinued operations	0	2	79
Midwest Generation LLC [Member]
Cash Flows From Operating Activities
Net loss (income)	(633)	(1,464)	(270)
Adjustments to reconcile (loss) income to net cash provided by operating activities:
Non-cash reorganization items	26	6	0
Depreciation and amortization	119	129	160
Deferred taxes and tax credits	(19)	54	(145)
Loss on disposal and asset impairments	465	14	653
Impairment of loan to affiliate	0	1,378	0
Changes in operating assets and liabilities:
Decrease (increase) in inventory	71	(6)	(36)
(Increase) decrease in due to/from affiliates	(4)	(64)	28
(Increase) decrease in prepaid expenses and other	3	(3)	(25)
Decrease in emission allowances	0	0	2
Increase (decrease) in payables and other current liabilities	3	(34)	(7)
Increase (decrease) in interest payable	2	(5)	(4)
Decrease (increase) in derivative assets and liabilities	1	6	1
(Decrease) increase in other operating—liabilities	9	2	7
Operating cash flows from continuing operations	43	13	364
Cash Flows From Financing Activities
Cash distributions to parent	0	0	(225)
Repayments of lease financing	(6)	(116)	(109)
Net cash used in financing activities	(6)	(116)	(334)
Cash Flows From Investing Activities
Capital expenditures	(16)	(30)	(103)
Proceeds from sale of assets	1	3	0
Proceeds from settlement of insurance claims	0	2	0
Increase in restricted deposits and restricted cash and cash equivalents	1	(2)	0
Investment in other assets	0	0	(18)
Repayment of loan to affiliate	0	12	9
Investing cash flows from continuing operations	(14)	(15)	(112)
Net (decrease) increase in cash and cash equivalents from continuing operations	23	(118)	(82)
Cash and cash equivalents at beginning of period from continuing operations	95	213	295
Cash and cash equivalents at end of period from continuing operations	$ 118	$ 95	$ 213