Post-Retirement and Similar Obligations - Additional Information (Detail)	3 Months Ended	9 Months Ended
Sep. 30, 2016 USD ($)	Sep. 30, 2016 USD ($)
Compensation And Retirement Disclosure [Abstract]
Defined benefit, pension contributions	$ 29,000,000	$ 44,000,000
Additional contributions for remainder of fiscal year	$ 0	$ 0

The amount of cash or cash equivalents contributed during the reporting period by the entity to fund its pension plans and its non-pension postretirement benefit plans.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3536-108585

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