Debt - Schedule of Uncommitted Bilateral Credit Facilities and Surety Bond Arrangements (Parenthetical) (Detail) $ in Millions	Dec. 31, 2018 USD ($)
Bank Guarantee and Bilateral Letter of Credit [Member]
Debt Instrument [Line Items]
Capacity available upon provision of cash collateral	$ 175
Surety Bonds [Member]
Debt Instrument [Line Items]
Debt instrument, collateral amount	402
Bank Guarantee [Member]
Debt Instrument [Line Items]
Debt instrument, collateral amount	$ 69

Amount of assets pledged to secure a debt instrument.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Name:	us-gaap_DebtInstrumentCollateralAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant