Taxes on Income (Loss) (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Loss Carryforwards [Line Items]
Deferred tax assets	$ 1,871	$ 1,866
Valuation allowance recorded against deferred tax assets	231	273
Remaining deferred tax assets to be realized	$ 2,011	$ 1,973
Effective tax rate	(388.00%)	48.00%	48.00%
Decrease in provision for income taxes	$ 267
Undistributed earnings in foreign subsidiaries	650
Tax liability including impact of foreign withholding taxes	250
Total unrecognized tax benefits	57	$ 11	$ 19	$ 41
Reversal of unrecognized tax benefits within next twelve months	46
Net, after-tax interest and penalties recognized	1	(1)	$ 1
Net, after-tax interest and penalties accrued	3	$ 3
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Deferred tax assets	1,523
NOL carryforwards	4,351
Federal NOL carry forwards	4,486
Federal NOL carry forwards, related to excess tax deductions	135
Associated tax benefits	47
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	26
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Deferred tax assets	166
Valuation allowance recorded against deferred tax assets	16
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Deferred tax assets	166
NOL carryforwards	804
NOL carry forward, valuation allowance	148
NOL carry forward with indefinite carry forward period	570
Deferred tax assets associated with indefinite carry forward period	107
NOL subject to expiration	234
Deferred tax assets associated with NOL subject to expiration	$ 59