Summary Of Significant Accounting Policies Summary of Significant Accounting Policies (Supplemental Cash Flow Information) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Cash Flow Information [Line Items]
Interest Paid, Capitalized		$ 17	$ 18	$ 37
Interest Paid, Net		335	333	393
Income Taxes Paid, Net		(15)	(27)	8
Continuing Operations
Supplemental Cash Flow Information [Line Items]
Interest Paid, Capitalized		17	18	20
Interest Paid, Net	[1]	335	333	362
Income Taxes Paid, Net		(17)	(41)	116
Discontinued Operations
Supplemental Cash Flow Information [Line Items]
Interest Paid, Capitalized		0	0	17
Interest Paid, Net	[2]	0	0	31
Income Taxes Paid, Net		$ 2	$ 14	$ (108)

[1] (a)Net of $17 million, $18 million, and $20 million capitalized, respectively.

[2] (b)Net of $- million, $- million, and $17 million capitalized, respectively.