Notes Receivable - Composition of our Notes Receivable Balances (Net of Reserves and Unamortized Discounts) (Detail) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Receivables [Abstract]    
Senior, mezzanine, and other loans $ 245 $ 242
Less current portion (91) (27)
Notes receivable, noncurrent $ 154 $ 215