Comprehensive Income (Loss) (Reclassification Out of AOCI) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes		$ (66)	$ 57	$ (147)	$ 113
Tax impact		38	(19)	68	(36)
Net income (loss)				(79)	77
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension Benefits [Member] | Amortization Of Defined Benefit Cost Items [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Actuarial gains/(losses)	[1],[2]	(6)	(4)	(13)	(9)
Tax impact	[1],[2]	2	1	5	3
Net income (loss)	[1],[2]	(4)	(3)	(8)	(6)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Postretirement Costs [Member] | Amortization Of Defined Benefit Cost Items [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Prior-service costs	[1]	1	1	2	2
Actuarial gains/(losses)	[1],[2]	(2)		(5)	(1)
Income before income taxes	[1],[2]	(1)	1	(3)	1
Tax impact	[1],[2]			1
Net income (loss)	[1],[2]	$ (1)	$ 1	$ (2)	$ 1

[1] Amounts in parentheses indicate losses.

[2] These accumulated other comprehensive loss components are included in the computation of net periodic pension and OPEB costs (see Note 14 - Retirement Plans for additional details).