Fair Value of Financial Instruments - Carrying Values and Fair Values of Non-Current Financial Assets and Liabilities (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior, mezzanine, and other loans	$ 154	$ 215
Other noncurrent liabilities	(927)	(891)
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior, mezzanine, and other loans	154	215
Marketable securities	42	44
Total noncurrent financial assets	196	259
Senior Notes	(1,985)	(2,272)
Commercial paper	(1,211)	(1,072)
Other long-term debt	(103)	(108)
Other noncurrent liabilities	(57)	(57)
Total noncurrent financial liabilities	(3,356)	(3,509)
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior, mezzanine, and other loans	153	214
Marketable securities	41	44
Total noncurrent financial assets	194	258
Senior Notes	(2,047)	(2,370)
Commercial paper	(1,211)	(1,072)
Other long-term debt	(114)	(122)
Other noncurrent liabilities	(57)	(57)
Total noncurrent financial liabilities	$ (3,429)	$ (3,621)