Income Taxes - Operating Loss Carryforwards (Details) (State and Local Jurisdiction [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2012
General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 12,000
Tax Credit Carryforward, Amount	12
Expiration Period, 2013-2017 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	292
Tax Credit Carryforward, Amount	2
Expiration Period, 2018-2022 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	336
Expiration Period, 2023-2027 [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	2,500
Expiration Period, 2028 and Thereafter [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	8,900
No Expiration [Member]
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Amount	$ 10