Contingencies - Tronox Litigation (Detail) (Tronox Litigation [Member], Judicial Ruling [Member], USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2014
Loss Contingencies [Line Items]
Litigation-related contingent liability	$ 0	$ 5,150,000,000		$ 5,210,000,000
Payment for Tronox settlement	5,200,000,000
Litigation-related contingent loss	5,000,000	4,300,000,000	850,000,000
Post Settlement Interest Expense [Member]
Loss Contingencies [Line Items]
Litigation-related contingent loss	$ 5,000,000			$ 60,000,000