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Financial Instruments and Risk Management - Schedule of Financial Assets (Liabilities) Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration on business combinations		$ (12)
Total	$ 320	479
Derivative Financial Instruments, Liabilities [Member] \| Not Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	(1)	(1)
U.S. Treasury Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities issued by foreign governments	330	431
Equity Securities [Member] \| Fair Value Through Earnings [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities issued by foreign governments	19
Equity Securities [Member] \| Held-for-Trading Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities issued by foreign governments		9
Equity Securities [Member] \| Available-for-Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities issued by foreign governments		11
Derivative Financial Instruments, Assets [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments		37
Derivative Financial Instruments, Assets [Member] \| Not Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	3	4
Derivative Financial Instruments, Assets [Member] \| Held-for-Trading Securities [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities issued by foreign governments	2
Derivative Financial Instruments, Assets [Member] \| Derivative Financial Instruments, Liabilities [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	(33)
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	349	451
Fair Value, Inputs, Level 1 [Member] \| U.S. Treasury Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities issued by foreign governments	330	431
Fair Value, Inputs, Level 1 [Member] \| Equity Securities [Member] \| Fair Value Through Earnings [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities issued by foreign governments	19
Fair Value, Inputs, Level 1 [Member] \| Equity Securities [Member] \| Held-for-Trading Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities issued by foreign governments		9
Fair Value, Inputs, Level 1 [Member] \| Equity Securities [Member] \| Available-for-Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities issued by foreign governments		11
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	(29)	40
Fair Value, Inputs, Level 2 [Member] \| Derivative Financial Instruments, Liabilities [Member] \| Not Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	(1)	(1)
Fair Value, Inputs, Level 2 [Member] \| Derivative Financial Instruments, Assets [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments		37
Fair Value, Inputs, Level 2 [Member] \| Derivative Financial Instruments, Assets [Member] \| Not Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	3	4
Fair Value, Inputs, Level 2 [Member] \| Derivative Financial Instruments, Assets [Member] \| Held-for-Trading Securities [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities issued by foreign governments	2
Fair Value, Inputs, Level 2 [Member] \| Derivative Financial Instruments, Assets [Member] \| Derivative Financial Instruments, Liabilities [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	$ (33)
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration on business combinations		(12)
Total		$ (12)