Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Feb. 12, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset sales	$ 394	$ 0
Carrying value of assets sold			235
Discontinued operations, goodwill			29
Pre-tax income from discontinued operation	155	6
Pre-tax gain on sale of assets	142
Revenues from discontinued operations	5	6
FES
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset sales	307	17
Carrying value of assets sold			122
Discontinued operations, goodwill			1
Pre-tax income from discontinued operation	186	5
Pre-tax gain on sale of assets	177
Revenues from discontinued operations	$ 5	$ 6