Supplemental Data Supplemental Data (Summary of Accounts Receivable, Net) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
From Customers	$ 2,346	$ 2,352
Other	376	328
Less allowance for doubtful accounts and sales discounts	(80)	(78)
Total	$ 2,642	$ 2,602