Income Taxes (Details 2) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Components of Deferred Tax Assets [Abstract]
Deferred Tax Assets, Operating Loss Carryforwards	$ 6,647	$ 6,472
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits	5,703	4,527
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	402	424
Deferred Tax Assets, Deferred Income	2,297	2,202
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Deferred Rent	284	280
Deferred Tax Assets Reorganization Items	395	674
Deferred Tax Assets, Other	564	495
Deferred Tax Assets, Valuation Allowance	(10,705)	(9,632)
Deferred Tax Assets, Net	5,587	5,442
Components of Deferred Tax Liabilities [Abstract]
Deferred Tax Liabilities, Property, Plant and Equipment	5,093	4,837
Deferred Tax Liabilities, Financing Arrangements	206	330
Deferred Tax Liabilities, Goodwill and Intangible Assets, Intangible Assets	1,755	1,731
Deferred Tax Liabilities, Derivatives	32	73
Deferred Tax Liabilities, Other	68	40
Deferred Tax Liabilities	7,154	7,011
Deferred Tax Assets (Liabilities), Net [Abstract]
Deferred Tax Assets (Liabilities), Net, Current	461	355
Deferred Tax Assets (Liabilities), Net, Noncurrent	(2,028)	(1,924)
Deferred Tax Assets (Liabilities), Net	$ (1,567)	$ (1,569)