Investments In Unconsolidated Affiliates (Summarized Combined Financial Information Of Equity Method Unconsolidated Affiliates - Balance Sheet) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Investments In Unconsolidated Affiliates And Related Party Transactions [Line Items]
Current assets	$ 10,122	$ 6,880
Current liabilities	(10,029)	(5,528)
Equity Method Investments [Member]
Investments In Unconsolidated Affiliates And Related Party Transactions [Line Items]
Current assets	577	492
Non-current assets	2,252	1,599
Current liabilities	(601)	(267)
Non-current liabilities	(579)	(225)
Net assets	$ 1,649	$ 1,599