Basis of Presentation Basis of Presentation (Out-of-period-correction) (Details) $ in Millions	3 Months Ended
Mar. 31, 2017 USD ($)
Income Tax Provision [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Benefit related to an out-of-period correction for a reversal of a tax reserve	$ 20

Amount of each individual error being corrected in the correcting adjustment.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 1.N)
-URI http://asc.fasb.org/extlink&oid=26874127&loc=d3e30840-122693

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