Reclassifications From Accumulated Other Comprehensive Income (Loss) (Amounts Reclassified From Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net actuarial loss	[1]	$ 4		$ 4
General and administrative expenses		56	$ 60	110	$ 128
Provision (benefit) for income taxes		(1)	(493)		(444)
Net Loss		$ (593)	$ (788)	(1,725)	$ (710)
Pension And Other Postretirement [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
General and administrative expenses				1
Provision (benefit) for income taxes				$ 1

[1] Net of $1 million in taxes for the three and six months ended June 30, 2016.