Schedule I - Condensed Financial Information Of Parent Company (Balance Sheets) (Details) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
CURRENT ASSETS
Cash and cash equivalents	$ 109	$ 20	$ 44
Prepayments of income taxes	74	276
Total Current Assets	1,439	1,757
INVESTMENTS AND OTHER ASSETS
Goodwill	1,407	1,407	1,407
Other	163	169
Total Investments and Other Assets	5,251	5,050
TOTAL ASSETS	14,910	14,480
CURRENT LIABILITIES
Short-term debt	732	534
Total Current Liabilities	1,861	1,797
DEFERRED CREDITS
Liabilities and accrued interest related to uncertain tax positions	32	148
Long-term debt	3,794	3,629
COMMITMENTS AND CONTINGENCIES
EQUITY
Common stock	2	2
Premium on stock and other capital contributions	3,325	3,275
Accumulated other comprehensive loss	(63)	(106)	(138)	(155)
Retained earnings	1,072	1,059
Total Equity	4,336	4,236
TOTAL LIABILITIES AND EQUITY	14,910	14,480
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares outstanding	227,500,190	225,082,252
Parent Company [Member]
CURRENT ASSETS
Cash and cash equivalents	257	131	585	556
Prepayments of income taxes	51	99
Accounts receivable and other	7	8
Total Current Assets	315	238
INVESTMENTS AND OTHER ASSETS
Goodwill	1,398	1,398
Notes receivable from subsidiary companies	154	154
Investment in consolidated companies	3,654	3,033
Other	24	19
Investments held for sale		355
Total Investments and Other Assets	5,230	4,959
TOTAL ASSETS	5,545	5,197
CURRENT LIABILITIES
Short-term debt	465	230
Interest and taxes accrued	11	15
Accounts payable due to associated companies	25	3
Total Current Liabilities	501	248
DEFERRED CREDITS
Liabilities and accrued interest related to uncertain tax positions	3	14
Long-term debt	705	705
EQUITY
Common stock	2	2
Premium on stock and other capital contributions	3,325	3,275
Accumulated other comprehensive loss	(63)	(106)
Retained earnings	1,072	1,059
Total Equity	4,336	4,230
TOTAL LIABILITIES AND EQUITY	$ 5,545	$ 5,197