Reclassifications From Accumulated Other Comprehensive Income (Amounts Reclassified From Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
General and administrative expenses	$ 54	$ 68
Provision for income taxes	1	49
Net Income (Loss)	(1,132)	$ 78
Pension And Other Postretirement [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
General and administrative expenses	2
Provision for income taxes	1
Net Income (Loss)	$ 1