Goodwill And Other Intangibles (Expenses Related To Emissions And Renewable Energy Requirements) (Details) - Power [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Emissions Expense	$ 14	$ 13	$ 10
Renewable Energy Expense	$ 95	$ 91	$ 59