XML 141 R91.htm IDEA: XBRL DOCUMENT v2.4.0.6
Investments in Affiliates (Schedule of Transactions with Affiliates) (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Investments in and Advances to Affiliates, Schedule of Investments [Abstract]      
Purchases $ 163 $ 190 $ 169
Sales 1 10 8
Interest income $ 0 $ 1 $ 1