Condensed Consolidated Statements of Operations (Parenthetical) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Income Statement [Abstract]
Interest income	$ 2,000,000	$ 3,000,000	$ 3,000,000	$ 6,000,000
Income (loss) from discontinued operations, income tax (provision) benefit	$ 1,000,000	$ (3,000,000)	$ 1,000,000	$ 0

Tax effect allocated to a disposal group that is classified as a component of the entity reported as a separate component of income before extraordinary items and the cumulative effect of accounting changes. Includes the tax effects of the following: income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 43

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 47
-Subparagraph c

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 46

Name:	us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration