Equity Investments (Schedule of Financial Information Related to Unconsolidated Entities Included in Consolidated Statement of Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Equity Investments [Abstract]
Revenues	$ 332	$ 315
Operating costs and expenses	294	283
Income from continuing operations before taxes	$ 39	$ 32

The amount of income (loss) from continuing operations before extraordinary items reported by an equity method investment of the entity.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

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-Subparagraph 1, 2

-Article 4

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

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-Article 1

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration