Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Millions		Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		$ 4,753	$ 1,600
Total assets	[1]	156,199	159,422
Total liabilities		577	1,024
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		12,801	19,595
Total liabilities		577	1,024
Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		4,753	1,600
Available-for-sale debt securities		5,027	15,091
Total short-term investments		9,780	16,691
Other Current Assets [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative assets		412	574
Other Current Assets [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative assets		79	97
Other Current Assets [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative assets		334	477
Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		430	491
Trading funds and securities		1,477	1,273
Total long-term investments		1,907	1,764
Other Noncurrent Assets [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative assets		702	566
Other Noncurrent Assets [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative assets		453	335
Other Noncurrent Assets [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative assets		249	232
Other Current Liabilities [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative liabilities		110	82
Other Current Liabilities [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative liabilities		1	5
Other Current Liabilities [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative liabilities		109	78
Other Noncurrent Liabilities [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative liabilities		467	942
Other Noncurrent Liabilities [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative liabilities		0	378
Other Noncurrent Liabilities [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative liabilities		467	564
Level 1 [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		1,467	1,260
Total liabilities		0	0
Level 1 [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		15	17
Available-for-sale debt securities		0	0
Total short-term investments		15	17
Level 1 [Member] | Other Current Assets [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative assets		0	0
Level 1 [Member] | Other Current Assets [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative assets		0	0
Level 1 [Member] | Other Current Assets [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative assets		0	0
Level 1 [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0	0
Trading funds and securities		1,452	1,243
Total long-term investments		1,453	1,243
Level 1 [Member] | Other Noncurrent Assets [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative assets		0	0
Level 1 [Member] | Other Noncurrent Assets [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative assets		0	0
Level 1 [Member] | Other Noncurrent Assets [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative assets		0	0
Level 1 [Member] | Other Current Liabilities [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative liabilities		0	0
Level 1 [Member] | Other Current Liabilities [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative liabilities		0	0
Level 1 [Member] | Other Current Liabilities [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative liabilities		0	0
Level 1 [Member] | Other Noncurrent Liabilities [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative liabilities		0	0
Level 1 [Member] | Other Noncurrent Liabilities [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative liabilities		0	0
Level 1 [Member] | Other Noncurrent Liabilities [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative liabilities		0	0
Level 2 [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets		11,334	18,335
Total liabilities		577	1,024
Level 2 [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		4,739	1,583
Available-for-sale debt securities		5,027	15,091
Total short-term investments		9,766	16,674
Level 2 [Member] | Other Current Assets [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative assets		412	574
Level 2 [Member] | Other Current Assets [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative assets		79	97
Level 2 [Member] | Other Current Assets [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative assets		334	477
Level 2 [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		430	491
Trading funds and securities		25	30
Total long-term investments		454	521
Level 2 [Member] | Other Noncurrent Assets [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative assets		702	566
Level 2 [Member] | Other Noncurrent Assets [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative assets		453	335
Level 2 [Member] | Other Noncurrent Assets [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative assets		249	232
Level 2 [Member] | Other Current Liabilities [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative liabilities		110	82
Level 2 [Member] | Other Current Liabilities [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative liabilities		1	5
Level 2 [Member] | Other Current Liabilities [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current derivative liabilities		109	78
Level 2 [Member] | Other Noncurrent Liabilities [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative liabilities		467	942
Level 2 [Member] | Other Noncurrent Liabilities [Member] | Recurring [Member] | Interest rate contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative liabilities		0	378
Level 2 [Member] | Other Noncurrent Liabilities [Member] | Recurring [Member] | Foreign exchange contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Noncurrent derivative liabilities		467	564
Money market funds [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		4,727	1,571
Money market funds [Member] | Level 1 [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		0	0
Money market funds [Member] | Level 2 [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		4,727	1,571
Equity [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	[2]	26	29
Equity [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	[2]	1,425	1,223
Equity [Member] | Level 1 [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	[2]	15	17
Equity [Member] | Level 1 [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	[2]	1,400	1,193
Equity [Member] | Level 2 [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	[2]	12	11
Equity [Member] | Level 2 [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	[2]	25	30
Trading Securities [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		53	50
Trading Securities [Member] | Level 1 [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		53	50
Trading Securities [Member] | Level 2 [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		0	0
Government and agency - non U.S. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		3,059	9,703
Government and agency - non U.S. [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		3,014	9,609
Government and agency - non U.S. [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		45	94
Government and agency - non U.S. [Member] | Level 1 [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0	0
Government and agency - non U.S. [Member] | Level 1 [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0	0
Government and agency - non U.S. [Member] | Level 2 [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		3,014	9,609
Government and agency - non U.S. [Member] | Level 2 [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		45	94
Corporate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities	[3]	2,398	5,878
Corporate [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,013	5,482
Corporate [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		385	397
Corporate [Member] | Level 1 [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0	0
Corporate [Member] | Level 1 [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		0	0
Corporate [Member] | Level 2 [Member] | Short-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		2,013	5,482
Corporate [Member] | Level 2 [Member] | Long-term Investments [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale debt securities		$ 385	$ 397

[1] Amounts may not add due to rounding.

[2] As of June 30, 2019, short-term equity securities of $11 million and long-term equity securities of $24 million are held in trust for benefits attributable to the former Pharmacia Savings Plus Plan. As of December 31, 2018, short-term equity securities of $11 million and long-term equity securities of $29 million are held in trust for benefits attributable to the former Pharmacia Savings Plus Plan.

[3] Primarily issued by a diverse group of corporations.