Income Taxes - Operating Loss Carryforward (Details) (USD $)	Dec. 31, 2012
U.S. Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 8,526,000,000
U.S. Internal Revenue Service (IRS) | Expiring, 2023
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	254,000,000
U.S. Internal Revenue Service (IRS) | Expiring, 2024
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	1,302,000,000
U.S. Internal Revenue Service (IRS) | Expiring, 2025
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	1,186,000,000
U.S. Internal Revenue Service (IRS) | Expiring, 2026
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	1,029,000,000
U.S. Internal Revenue Service (IRS) | Expiring, 2027
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	1,501,000,000
U.S. Internal Revenue Service (IRS) | Expiring, 2028
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	445,000,000
U.S. Internal Revenue Service (IRS) | Expiring, 2029
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	700,000,000
U.S. Internal Revenue Service (IRS) | Expiring, 2030
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	703,000,000
U.S. Internal Revenue Service (IRS) | Expiring, 2031
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	711,000,000
U.S. Internal Revenue Service (IRS) | Expiring, 2032
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	695,000,000
Foreign jurisdiction
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforward, Disregarded for Domestic Country Tax Purposes	6,400,000,000
State jurisdiction
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 7,300,000,000