Fair Value of Financial Instruments - Carrying Values and Fair Values of Non-Current Financial Assets and Liabilities (Detail) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior, mezzanine, and other loans	$ 227	$ 215
Other noncurrent liabilities	(1,091)	(1,010)
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior, mezzanine, and other loans	227	215
Marketable securities	35	37
Total noncurrent financial assets	262	252
Senior notes	(3,959)	(2,766)
Commercial paper	0	(938)
Other long-term debt	(94)	(99)
Other noncurrent liabilities	(62)	(63)
Total noncurrent financial liabilities	(4,115)	(3,866)
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior, mezzanine, and other loans	214	209
Marketable securities	35	37
Total noncurrent financial assets	249	246
Senior notes	(4,117)	(2,826)
Commercial paper	0	(938)
Other long-term debt	(109)	(108)
Other noncurrent liabilities	(62)	(63)
Total noncurrent financial liabilities	$ (4,288)	$ (3,935)