CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash Flows From Operating Activities
Net Income (loss)	$ (614)	$ (348)
Adjustments to reconcile income (loss) to net cash provided by (used in) operating activities:
Non-cash reorganization items, net	45	0
Equity in (income) loss from unconsolidated affiliates	(43)	(42)
Distributions from unconsolidated affiliates	26	15
Mark to Market on interest rate swaps	(6)	0
Depreciation and amortization	225	219
Deferred taxes and tax credits	(13)	(215)
Asset impairment and other charges	462	5
(Gain) loss on early extinguishment of debt	3	0
Proceeds from US Treasury Grants	0	44
Changes in operating assets and liabilities:
(Increase) decrease in margin and collateral deposits	(24)	(38)
(Increase) decrease in receivables	(6)	(38)
Decrease (increase) in inventory	54	(2)
Decrease (increase) in prepaid expenses and other	5	(16)
(Increase) decrease in restricted cash and cash equivalents	(5)	(2)
Decrease (increase) in rent payments in excess of levelized rent expense	37	(95)
Increase (decrease) in payables, other current liabilities and liabilities subject to compromise	30	35
Decrease (increase) in derivative assets and liabilities, net	35	(9)
Decrease (increase) in other operating—assets	2	(3)
(Decrease) increase in other operating—liabilities	(42)	(45)
Operating cash flows from continuing operations	171	(535)
Operating cash flows from discontinued operations, net	(2)	(5)
Net cash provided by (used in) operating activities	169	(540)
Cash Flows From Financing Activities
Cash contributions from noncontrolling interests	94	242
Borrowings under short-term debt	0	21
Borrowings under long-term debt	171	154
Payments on debt	(92)	(31)
Cash contribution from EIX related to the tax-allocation agreements	6	0
Cash dividends to noncontrolling interests	(11)	(14)
Payments to affiliates related to stock-based awards	(13)	(14)
Excess tax benefits related to stock-based exercises	2	3
Financing costs	(6)	(7)
Net cash provided by (used in) financing activities	151	354
Cash Flows From Investing Activities
Capital expenditures	(91)	(266)
Proceeds from sale of assets	4	1
Proceeds from return of capital and loan repayments from unconsolidated affiliates	11	7
Proceeds from settlement of insurance claims	2	1
Cash settlement with turbine manufacturer	5	0
Investments in and loans to unconsolidated affiliates	(3)	0
(Increase) decrease in restricted deposits and restricted cash and cash equivalents	0	(76)
Investment in other assets	0	(9)
Investing cash flows from continuing operations	(72)	(342)
Investing cash flows from discontinued operations, net	0	(19)
Net cash provided by (used in) investing activities	(72)	(361)
Net increase (decrease) in cash and cash equivalents from continuing operations	250	(523)
Cash and cash equivalents at beginning of period from continuing operations	888	1,221
Cash and cash equivalents at end of period from continuing operations	1,138	698
Net (decrease) increase in cash and cash equivalents from discontinued operations	(2)	(24)
Cash and cash equivalents at beginning of period from discontinued operations	2	79
Cash and cash equivalents at end of period from discontinued operations	0	55
Midwest Generation LLC
Cash Flows From Operating Activities
Net Income (loss)	(619)	(63)
Adjustments to reconcile income (loss) to net cash provided by (used in) operating activities:
Non-cash reorganization items, net	27	0
Depreciation and amortization	95	96
Deferred taxes and tax credits	(2)	(29)
Asset impairment and other charges	465	5
Changes in operating assets and liabilities:
Decrease in due to/from affiliates, net	3	70
Decrease (increase) in inventory	63	(2)
Decrease (increase) in prepaid expenses and other	(3)	(5)
Increase (decrease) in payables, other current liabilities and liabilities subject to compromise	3	(9)
Increase (decrease) in interest payable	5	(12)
Decrease (increase) in derivative assets and liabilities, net	2	5
(Decrease) increase in other operating—liabilities	7	1
Net cash provided by (used in) operating activities	46	57
Cash Flows From Financing Activities
Repayments of lease financing	(6)	(116)
Net cash used in financing activities	(6)	(116)
Cash Flows From Investing Activities
Capital expenditures	(17)	(24)
Proceeds from sale of assets	1	0
Proceeds from settlement of insurance claims	0	1
(Increase) decrease in restricted deposits and restricted cash and cash equivalents	1	(1)
Repayment of loan from affiliate	0	12
Net cash provided by (used in) investing activities	(15)	(12)
Net increase (decrease) in cash and cash equivalents from continuing operations	25	(71)
Cash and cash equivalents at beginning of period from continuing operations	95	213
Cash and cash equivalents at end of period from continuing operations	$ 120	$ 142