Interest rate stated in the contractual debt agreement.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Debt (Preceding Credit Facility and 8 7/8 Senior Notes) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		12 Months Ended
	Aug. 31, 2011	Jul. 31, 2011	Dec. 31, 2011 8.875% Senior Notes	Dec. 31, 2012 8.875% Senior Notes
Debt Instrument
Stated interest rate on debt instrument				8.875%
Amount of debt retired	$ 44	$ 133
8 7/8% callable amounts - July 2011		103.333%
8 7/8% callable amounts - August 2011	102.958%
Expenses related with debt extinguishment			$ 12