Inventories - Net of Allowance for Obsolete Inventories and Supplies (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2012 Successor	Dec. 31, 2011 Successor
Inventory on Consignment to Others	$ 65	$ 42	$ 42	$ 12
Fair value of inventory from the acquired mineral sands business		$ 553

The amount of acquisition cost of a business combination allocated to inventory, including finished goods, work-in-process, and raw materials.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph e

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 37

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsInventory
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant