Recent Accounting Guidance Not Yet Adopted (Narrative) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other assets	$ 468us-gaap_OtherAssetsNoncurrent	$ 483us-gaap_OtherAssetsNoncurrent
Accounting Standards Update 2015-03 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other assets	$ 79	$ 83

Aggregate carrying amount, as of the balance sheet date, of noncurrent assets not separately disclosed in the balance sheet. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

Name:	us-gaap_OtherAssetsNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant