Financial Information for Parent Issuer, Guarantor Subsidiaries and Non-Guarantor Subsidiaries (Details Textual) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
Mar. 31, 2011	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financial Information for Parent Issuer Guarantor Subsidiaries and Non-Guarantor Subsidiaries Disclosure [Abstract]
Senior notes issued	$ 800	$ 0	$ 522	$ 0
Percentage of ownership in wholly on subsidiary by parent		100.00%

The cash inflow from a debt funding received on a regular basis with maturities ranging from 5-10 years.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585

Name:	us-gaap_ProceedsFromIssuanceOfMediumTermNotes
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration