For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13537-108611

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Business Segment and Geographic Information (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) Division	Dec. 31, 2014 USD ($)	Dec. 31, 2013
Segment Reporting Information [Line Items]
Assets	$ 36,942	$ 32,165
Number of business segments \| Division	2
Shared assets
Segment Reporting Information [Line Items]
Assets	$ 1,785	$ 1,930
Property, Plant and Equipment [Member] \| UNITED STATES
Segment Reporting Information [Line Items]
Concentration Risk, Percentage	51.00%	46.00%
Sales Revenue, Net [Member] \| UNITED STATES
Segment Reporting Information [Line Items]
Concentration Risk, Percentage	44.00%	51.00%	49.00%