Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Income Taxes [Line Items]
Unrecorded tax benefit	$ 880,000,000
Federal pre-tax NOL carry forwards	10,000,000,000
Tax benefits of net operating losses	205,000,000
Less: accumulated amortization	4,137,000,000	4,171,000,000
Current valuation allowances	4,100,000,000
Decrease in current valuation allowances		34,000,000
Unrecognized tax benefits	24,000,000	32,000,000	16,000,000	20,000,000
Change in unrecognized tax benefits during the period	22,000,000
Maximum [Member]
Income Taxes [Line Items]
NOL carry forwards expiration period, years	20
Minimum [Member]
Income Taxes [Line Items]
NOL carry forwards expiration period, years	5
2022 [Member]
Income Taxes [Line Items]
Net operating loss expiration amount	1,200,000,000
2023 [Member]
Income Taxes [Line Items]
Net operating loss expiration amount	1,600,000,000
2024 [Member]
Income Taxes [Line Items]
Net operating loss expiration amount	2,400,000,000
2025 [Member]
Income Taxes [Line Items]
Net operating loss expiration amount	2,000,000,000
Thereafter [Member]
Income Taxes [Line Items]
Net operating loss expiration amount	$ 2,800,000,000