Schedule I - Condensed Parent Company Financial Statements (Balance Sheets) (Details) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2011		Sep. 30, 2011	Dec. 31, 2010		Dec. 31, 2009		Dec. 31, 2008
Cash and cash equivalents	$ 2,110			$ 1,670		$ 1,542		$ 986
Short-term investments	190
Receivables	784			764
Other	1,051			1,169
Total current assets	6,880			6,223
Notes receivable	62			42
Other	2,231			2,291
Total investments and other assets	9,160			9,255
Total Assets	62,526	[1]		59,090	[1]	57,040	[1]
Accounts payable	1,433			1,387
Notes payable and commercial paper	154
Taxes accrued	431			412
Other	1,091			1,370
Total current liabilities	5,528			3,897
Long-term Debt	17,730			16,959
Deferred income taxes	7,581			6,978
Total deferred credits and other liabilities	15,454			14,605
Commitments and Contingencies
Common Stock	1			1
Additional paid-in capital	21,132			21,023
Retained earnings	1,873			1,496
Accumulated other comprehensive (loss) income	(234)			2
Total common stockholder's equity	22,772			22,522
Total Liabilities and Equity	62,526			59,090
Common stock, par value	$ 0.001			$ 0.001
Common stock, shares authorized	2,000,000,000			2,000,000,000
Common stock, shares outstanding	1,336,000,000			1,329,000,000
Parent Company [Member]
Cash and cash equivalents	845			488		365		5
Receivables	653			913
Other	100			34
Total current assets	1,598			1,435
Notes receivable	450			450
Investment in consolidated subsidiaries	25,670			24,410
Other	571			525
Total investments and other assets	26,691			25,385
Total Assets	28,289			26,820
Accounts payable				138
Notes payable and commercial paper	154		75
Taxes accrued	35			39
Other	65			58
Total current liabilities	254			235
Long-term Debt	4,328			3,222
Deferred income taxes	16
Other	919			841
Total deferred credits and other liabilities	935			841
Common Stock	1			1
Additional paid-in capital	21,132			21,023
Retained earnings	1,873			1,496
Accumulated other comprehensive (loss) income	(234)			2
Total common stockholder's equity	22,772			22,522
Total Liabilities and Equity	$ 28,289			$ 26,820

[1] Includes assets held for sale and assets of entities in discontinued operations. See Note 13 for description and carrying value of investments accounted for under the equity method of accounting within each segment.