Commitments and Contingencies (Schedule of Variable Interest Entities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Variable Interest Entity [Line Items]
Property, plant and equipment, net	$ 3,286	$ 3,350
Trade payables	659	649
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Property, plant and equipment, net	116	118
Trade payables	43	41
Current installments of long-term debt	7	7
Long-term debt	139	140
Total	189	188
Maximum exposure to loss	$ 273	$ 273