Subsequent Events (Details) (USD $) In Millions, unless otherwise specified			0 Months Ended
Sep. 30, 2013	Sep. 30, 2013 7 % Senior Notes due 2013	Dec. 31, 2012 7 % Senior Notes due 2013	Oct. 02, 2013 Subsequent event 7 % Senior Notes due 2013
Subsequent events
Principal balance of debt redeemed				$ 451
Interest rate (as a percent)	7.00%	7.00%	7.00%	7.00%

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

Name:	us-gaap_RepaymentsOfLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration