Income Taxes (Effective Income Tax Rate) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Income tax benefit at the federal statutory rate	$ (1,460)	$ (923)	$ (1,155)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	35.00%
State income taxes, net of federal income tax effect	137	80	118
State law changes, net of federal income tax effect	5	38	0
Income Tax Reconciliation Reduction In Unrecognized Tax Benefits	(38)	1	(18)
Tax expense related to equity awards	(15)	(13)	(42)
Change in valuation allowance	(1,756)	(1,221)	(1,418)
Other, net	(13)	16	3
Income tax (expense) benefit	$ 154	$ 254	$ 166
Effective income tax rate	(3.70%)	(9.60%)	5.00%