Financings And Capitalization (Issuance Of Common Stock) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended		24 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016
Financings And Capitalization [Abstract]
Number of Shares Issued	1,449,171	888,610	2,337,781
Average Price Per Share	$ 41.40	$ 33.76	$ 38.50
Proceeds	$ 60	$ 30	$ 90