Income Taxes Income Taxes - Additional Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes Other Information [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	35.00%	35.00%	35.00%	[1]
Deferred Tax Assets, Valuation Allowance	$ 56	$ 65
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	92
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound	65
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	18	21
Unrecognized Tax Benefits, Interest on Income Taxes Expense	$ 3	$ 1
Income Tax Examination, Description	The Company's federal income tax returns are no longer subject to examination by the IRS for taxable years prior to 2006. The IRS audit of the 2006 federal income tax return is closed, but the return is still subject to examination to the extent of carryback claims. The Company's 2007 through 2009 federal income tax returns are currently under examination by the IRS. With limited exceptions, the Company is no longer subject to examination by state and local taxing authorities for taxable years prior to 2006.

[1] "NM" - Calculated percentage was not considered to be meaningful