Contingencies - Tronox Litigation (Detail) - Tronox Litigation [Member] - Judicial Ruling [Member] - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Apr. 03, 2014
Loss Contingencies [Line Items]
Litigation-related contingent liability		$ 5,150		$ 0	$ 5,210
Pre Settlement Interest Rate							6.00%
Post Settlement Interest Rate First 180 Days							1.50%
Payment for Tronox settlement	$ 5,200
Litigation-related contingent loss		4,300	$ 850	$ 5	4,360	$ 850
London Interbank Offered Rate (LIBOR) [Member]
Loss Contingencies [Line Items]
Post Settlement Interest Rate After 180 Days							1.50%
Excluding Pre-Judgment Interest Sought and Attorneys' Fees and Costs [Member]
Loss Contingencies [Line Items]
Damages sought		$ 18,850
Principal Portion Of Loss Contingency Accrual [Member]
Loss Contingencies [Line Items]
Litigation-related contingent liability							$ 3,980
Post Settlement Interest Expense [Member]
Loss Contingencies [Line Items]
Litigation-related contingent loss	$ 5				$ 60