Financial Instruments and Fair Value Measurements - Summary of Debt and Accrued Interest, Designated as Hedge (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Derivatives Fair Value [Line Items]
Senior Notes Outstanding	$ 8,300
Designated As Hedging Instrument [Member] \| British Pound Sterling Senior Notes [Member]
Derivatives Fair Value [Line Items]
Senior Notes Outstanding	346	$ 269
Designated As Hedging Instrument [Member] \| Euro Senior Notes [Member]
Derivatives Fair Value [Line Items]
Senior Notes Outstanding	$ 3,028	$ 2,645

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16(a))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Name:	us-gaap_SeniorNotes
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant