Principles of Consolidation and Other Matters Investment Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Investment income	$ 2us-gaap_InvestmentIncomeNonoperating	$ 13us-gaap_InvestmentIncomeNonoperating

The aggregate amount of income from investments (for example, dividends) not considered a component of the entity's core operations.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Article 5

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