Comprehensive Income (Loss) (Reclassification Out of AOCI) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	$ (81)		$ 56
Tax impact	30		(17)
Net income (loss)	(51)		39
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)	(7)	[1],[2]	(5)	[1],[2]
Tax impact	3	[1],[2]	2	[1],[2]
Net income (loss)	(4)	[1],[2]	(3)	[1],[2]
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],[2]	1	[1],[2]
Actuarial gains/(losses)	(3)	[1]	(1)	[1]
Income before income taxes	(2)	[1],[2]
Tax impact	1	[1],[2]
Net income (loss)	$ (1)	[1],[2]

[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 13 - Retirement Plans for additional details).