Income Taxes Level 4 (Details) - Presentation of the Net Deferred Tax Liability - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets
Long-term deferred income taxes	$ 8	$ 10
Liabilities [Abstract]
Long-term deferred income taxes	(11)	(13)
Net deferred tax liability	(3)	(3)
net operating loss carryforward reduction	26
Valuation allowance	(522)	651	$ 611	$ 588
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	1,158
Tax Credit Carryforward, Amount	2
Valuation allowance on state net operating loss carryforwards	90
Operating Loss Carryforwards, Valuation Allowance	130
Unrepatriated earnings of foreign subsidiaries	$ (9)	$ (9)