Restructuring Activities (Details) (USD $)	1 Months Ended	12 Months Ended					0 Months Ended	1 Months Ended	12 Months Ended	3 Months Ended	1 Months Ended		0 Months Ended	3 Months Ended	12 Months Ended					0 Months Ended	12 Months Ended
	Apr. 30, 2013 positions	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 16, 2012	Nov. 15, 2012	Mar. 12, 2014 Subsequent Event claims	Feb. 28, 2014 Subsequent Event	Dec. 31, 2013 Subsequent Event installment_payments zero_coupon_promissory_notes	Jun. 30, 2012 Edison Mission Energy positions	Dec. 31, 2013 Midwest Generation LLC [Member]	Apr. 30, 2013 Midwest Generation LLC [Member] positions	Jan. 02, 2013 Midwest Generation LLC [Member]	Jun. 30, 2012 Midwest Generation LLC [Member] positions	Dec. 31, 2013 Midwest Generation LLC [Member]	Dec. 31, 2012 Midwest Generation LLC [Member]	Dec. 31, 2011 Midwest Generation LLC [Member]	Jan. 02, 2014 Midwest Generation LLC [Member]	Jul. 02, 2013 Midwest Generation LLC [Member]	Mar. 12, 2014 Midwest Generation LLC [Member] Subsequent Event claims	Dec. 31, 2013 Other EME Subsidiaries	Dec. 31, 2012 Other EME Subsidiaries	Dec. 31, 2013 Accrued Rejected Contracts [Member] Midwest Generation LLC [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated	150											120
Business Acquisition, Future Capital Commitment Limit		$ 350,000,000
Number claims received (claims)							766													303
Provision for allowable claims		19,000,000	6,000,000												19,000,000	6,000,000					0	0
Senior notes, net		3,700,000,000	3,700,000,000
Write off of unamortized deferred financing costs and debt discounts		0	15,000,000												0	0					0	15,000,000
Professional fees		101,000,000	22,000,000												22,000,000	0					79,000,000	22,000,000
Total reorganization items, net		120,000,000	43,000,000	0											41,000,000	6,000,000	0				79,000,000	37,000,000
Interest payable on liabilities subject to compromise		154,000,000	154,000,000		38,000,000	97,000,000					11,000,000				11,000,000	13,000,000
Contractual interest expense on liabilities subject to compromise not reflected in statement of operations		281,000,000	11,000,000												13,000,000
Accounts payable and accrued liabilities		53,000,000	32,000,000								42,000,000				42,000,000	29,000,000							32,000,000
Lease payments not paid													76,000,000					76,000,000	76,000,000
Rent paid for sales leaseback transaction											10,000,000		7,000,000		30,000,000
Severance and other employee benefits due to employees affected by planned shutdowns	7,000,000									9,000,000		5,000,000		6,000,000
Number of expected positions to be eliminated (positions)										200				175
Business Acquisition, Cost of Acquired Entity, Purchase Price		2,635,000,000
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned		350,000,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares		12,671,977
Business Acquisition, Termination Fee		65,000,000
Tax attributes estimated amount								1,190,000,000
Liabilities assumed, net								241,000,000
EIX Estimated Liabilities Assumed								350,000,000
Percentage of tax benefits to be paid								50.00%
Cash portion of settlement payment									225,000,000
Related Party Transaction, Rate									5.00%
Number of installment payments									2
Number of zero coupon promissory notes									2
Escrow Deposit									$ 50,000,000