SCHEDULE I, CONDENSED FINANCIAL INFORMATION OF PARENT, BALANCE SHEETS (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Assets:
Schedule I, Condensed Financial Information of Parent, Cash and cash equivalents	$ 11	$ 157
Schedule I, Condensed Financial Information of Parent, Due from affiliates	112	27
Schedule I, Condensed Financial Information of Parent, Income taxes receivable		190
Schedule I, Condensed Financial Information of Parent, Other current assets	16	11
Schedule I, Condensed Financial Information of Parent, Total current assets	139	385
Schedule I, Condensed Financial Information of Parent, Investments in subsidiaries	12,272	11,484
Schedule I, Condensed Financial Information of Parent, Due from affiliates	1,730	1,683
Schedule I, Condensed Financial Information of Parent, Deferred income taxes	1,200	305
Schedule I, Condensed Financial Information of Parent, Other assets	548	488
Schedule I, Condensed Financial Information of Parent, Total assets	15,889	14,345
Liabilities and shareholders' equity:
Schedule I, Condensed Financial Information of Parent, Current portion of long-term debt	8	32
Schedule I, Condensed Financial Information of Parent, Current due to affiliates	1,014	1,331
Schedule I, Condensed Financial Information of Parent, Income taxes payable	246
Schedule I, Condensed Financial Information of Parent, Other current liabilities	336	374
Schedule I, Condensed Financial Information of Parent, Total current liabilities	1,604	1,737
Schedule I, Condensed Financial Information of Parent, Long-term debt	3,957	3,140
Schedule I, Condensed Financial Information of Parent, Other long-term liabilities	490	441
Schedule I, Condensed Financial Information of Parent, Shareholders' equity	9,838	9,027
Schedule I, Condensed Financial Information of Parent, Total liabilities and shareholders' equity	$ 15,889	$ 14,345