Fair Value Measurements Assets Fair Value Nonrecurring Basis (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of property, plant, and equipment	$ 59
Impairment of intangible assets (Excluding goodwill)	52
Impairment of goodwill	14	0
Impairment of other assets	4
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of property, plant, and equipment impaired during the period	109
Fair value of intangible assets measured on a non-recurring basis that was written down during the period	232
Fair Value of Property, Goodwill Impaired During the Period	0
Fair Value of other assets Impaired During the Period	$ 0