Income Taxes, Narrative (Details) $ in Millions	3 Months Ended
Mar. 31, 2018 USD ($)
Income Tax Disclosure [Abstract]
Income tax benefit, adjustment	$ 3

Amount of income tax expense (benefit) from continuing operations attributable to an adjustment of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319

Name:	us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration