Income Taxes Level 4 (Details) - Presentation of the Net Deferred Tax Liability - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Contingency [Line Items]
Income Tax Expense (Benefit)	$ 38	$ 34	$ 22
Assets
Long-term deferred income taxes	10	13
Liabilities [Abstract]
Long-term deferred income taxes	(13)	(12)
Net deferred tax (liability) asset	(3)	1
net operating loss carryforward reduction	26
Valuation allowance	651	$ 611	$ 588	$ 518
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	1,059
Tax Credit Carryforward, Amount	2
Operating Loss Carryforwards, Valuation Allowance	$ 83