Employee Benefit Plans - Schedule of Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Effect of one percentage point increase on accumulated postretirement benefit obligation	$ 4	$ 5
Effect of one percentage point decrease on accumulated postretirement benefit obligation	$ (4)	$ (4)

Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (m)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnAccumulatedPostretirementBenefitObligation1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration