Disclosures About Fair Value Measurements (Carrying Amounts, Estimated Fair Values And Impairment Expense Of Long-Lived Assets For Continuing And Discontinued Operations) (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Disclosure Disclosures About Fair Value Of Financial Instruments Carrying Amounts Estimated Fair Values And Impairment Expense Of Long Lived Assets For Continuing And Discontinued Operations [Abstract]
Carrying Amount	$ 3,438
Estimated Fair Value (Level 3)	1,913
Impairment Expense	$ 1,525