Pension and Postretirement Benefit Plans - Additional Information (Details) - Scenario, Forecast [Member] - Pension Plan [Member] - UNITED STATES $ in Millions	6 Months Ended
Jun. 30, 2019 USD ($) plan
Defined Benefit Plan Disclosure [Line Items]
Number of plans expected to be terminated \| plan	1
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Pre-tax charge at settlement	$ 330
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Pre-tax charge at settlement	$ 415

Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (h)(7)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration