Long-Term Debt Long-Term Debt Obligations (Detail) - USD ($)		Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Other long-term debt		$ 93,000,000	$ 312,000,000
Total debt		8,838,000,000	8,562,000,000
Credit Agreement, borrowings outstanding		0	0
Less current portion of long-term debt		(1,056,000,000)	(238,000,000)
Face value of long-term debt		$ 7,782,000,000	8,324,000,000
1.20% Notes due on November 29, 2017
Debt Instrument [Line Items]
Stated interest rate		1.20%
Total debt	[1]	$ 1,000,000,000	1,000,000,000
Effective interest rate		1.38%
2.60% Notes due on December 5, 2019
Debt Instrument [Line Items]
Stated interest rate		2.60%
Total debt	[2]	$ 1,000,000,000	1,000,000,000
Effective interest rate		2.73%
3.30% Notes due on December 5, 2021
Debt Instrument [Line Items]
Stated interest rate		3.30%
Total debt	[2]	$ 1,000,000,000	1,000,000,000
Effective interest rate		3.43%
2.50% Notes due on November 29, 2022
Debt Instrument [Line Items]
Stated interest rate		2.50%
Total debt	[1]	$ 1,250,000,000	1,250,000,000
Effective interest rate		2.66%
3.80% Notes due on December 5, 2024
Debt Instrument [Line Items]
Stated interest rate		3.80%
Total debt	[2]	$ 1,250,000,000	1,250,000,000
Effective interest rate		3.90%
4.80% Notes due on December 5, 2034
Debt Instrument [Line Items]
Stated interest rate		4.80%
Total debt	[2]	$ 1,250,000,000	1,250,000,000
Effective interest rate		4.92%
4.95% Notes due on December 5, 2044
Debt Instrument [Line Items]
Stated interest rate		4.95%
Total debt	[2]	$ 1,500,000,000	1,500,000,000
Effective interest rate		5.11%
October 2016 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit Agreement, borrowings outstanding		$ 495,000,000	$ 0

[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%.