Contingencies (NPM Adjustment Calculation) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Loss Contingencies [Line Items]
Partial Liability Reduction Percentage for 2003 NPM Adjustment for States that Are Party to Agreement re: Arbitration	20.00%
Challanges To MSA Found In Favor Of Defendants	16
Year NPM Adjustment Calculated 2013 [Member]
Loss Contingencies [Line Items]
Affiliates Maximum Potential NPM Adjustments	215
Year NPM Adjustment Calculated 2012 [Member]
Loss Contingencies [Line Items]
Affiliates Maximum Potential NPM Adjustments	207
Year Npm Adjustment Calculated2011 [Member]
Loss Contingencies [Line Items]
Affiliates Maximum Potential NPM Adjustments	165
Year Npm Adjustment Calculated2010 [Member]
Loss Contingencies [Line Items]
Affiliates Maximum Potential NPM Adjustments	219
Year NPM Adjustment Calculated 2009 [Member]
Loss Contingencies [Line Items]
Affiliates Maximum Potential NPM Adjustments	211
Year Npm Adjustment Calculated2008 [Member]
Loss Contingencies [Line Items]
Affiliates Maximum Potential NPM Adjustments	250
Year Npm Adjustment Calculated2007 [Member]
Loss Contingencies [Line Items]
Affiliates Maximum Potential NPM Adjustments	185
Year Npm Adjustment Calculated2006 [Member]
Loss Contingencies [Line Items]
Affiliates Maximum Potential NPM Adjustments	154
Year Npm Adjustment Calculated2005 [Member]
Loss Contingencies [Line Items]
Affiliates Maximum Potential NPM Adjustments	181
Year Npm Adjustment Calculated2004 [Member]
Loss Contingencies [Line Items]
Affiliates Maximum Potential NPM Adjustments	388