Long-Term Debt Long-Term Debt Obligations (Detail) - USD ($) $ in Millions		Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term debt		$ 8,827	$ 8,838
Other long-term debt		77	93
Less current portion of long-term debt		(1,049)	(1,056)
Face value of long-term debt		$ 7,778	7,782
1.20% Notes due on November 29, 2017
Debt Instrument [Line Items]
Stated interest rate		1.20%
Long-term debt	[1]	$ 1,000	1,000
Effective interest rates		1.38%
2.60% Notes due on December 5, 2019
Debt Instrument [Line Items]
Stated interest rate		2.60%
Long-term debt	[2]	$ 1,000	1,000
Effective interest rates		2.73%
3.30% Notes due on December 5, 2021
Debt Instrument [Line Items]
Stated interest rate		3.30%
Long-term debt	[2]	$ 1,000	1,000
Effective interest rates		3.43%
2.50% Notes due on November 29, 2022
Debt Instrument [Line Items]
Stated interest rate		2.50%
Long-term debt	[1]	$ 1,250	1,250
Effective interest rates		2.66%
3.80% Notes due on December 5, 2024
Debt Instrument [Line Items]
Stated interest rate		3.80%
Long-term debt	[2]	$ 1,250	1,250
Effective interest rates		3.90%
4.80% Notes due on December 5, 2034
Debt Instrument [Line Items]
Stated interest rate		4.80%
Long-term debt	[2]	$ 1,250	1,250
Effective interest rates		4.92%
4.95% Notes due on December 5, 2044
Debt Instrument [Line Items]
Stated interest rate		4.95%
Long-term debt	[2]	$ 1,500	$ 1,500
Effective interest rates		5.11%

[1] Issued in November 2012, effective interest rates of the 2017 and 2022 Notes were 1.38% and 2.66%.

[2] Issued in December 2014, effective interest rates of the 2019, 2021, 2024, 2034, and 2044 Notes were 2.73%, 3.43%, 3.90%, 4.92%, and 5.11%.