Debt (Schedule of Short-term Debt) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Short-term borrowings and current installments of long-term debt - third party and affiliates
Current installments of long-term debt	$ 38	$ 74
Short-term borrowings, including amounts due to affiliates, weighted average interest rate - 2011: 4.3%; 2010: 3.3%	106	154
Total	$ 144	$ 228
Weighted average interest rate	4.30%	3.30%