Discontinued Operations (Details) $ in Millions	1 Months Ended		3 Months Ended	6 Months Ended
	Aug. 31, 2014 USD ($) installment	Apr. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
EME settlement payments				$ 0	$ 225
Less: Income from discontinued operations			$ 184	$ 0	$ 162
Edison Mission Energy
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
EME settlement payments		$ 225
Number of payment installments | installment	2
First installment payment	$ 204
Second installment payment	$ 214