Financial Statement Presentation (Details 3) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$ 40	$ 100
Accounting Standards Update 2016-09 [Member]
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$ 40	$ 100
Excess Tax Benefit from Share-based Compensation, Operating Activities			$ 70

Amount of cash outflow for realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 20
-Section 55
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=96864182&loc=d3e11374-113907

Name:	us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration