Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Income Taxes
Effective tax rate on income from continuing operations (as a percent)	32.50%	29.70%	27.80%	20.70%
Capital loss carryforwards	$ 30		$ 30
Tax credits carryforward	103		103
Gross unrecognized tax benefit (expense)	168		168		75
Unrecognized tax benefits (net of federal tax benefits) that would impact the effective tax rate	44		44		54
Interest and penalties recognized			65	20
Accrued interest and penalties receivable	(36)		(36)		29
Estimated decrease in amount of unrecognized tax benefits in next 12 months, low end of the range	130		130
Estimated decrease in amount of unrecognized tax benefits in next 12 months, high end of the range	$ 140		$ 140

The tax effect as of the balance sheet date of the amount of future tax deductions arising from capital losses in excess of statutory limitations in historical filings, and which can only be utilized if sufficient tax-basis income is generated in future periods and providing tax laws continue to allow such utilization.

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The tax effect as of the balance sheet date of the amount of future tax deductions arising from all unused tax credit carryforwards which have been reduced by a valuation allowance.

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A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

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The amount of estimated penalties and interest accrued as of the balance sheet date arising from income tax examinations.

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The estimated lower bound of the reasonably possible change in the total amount of the unrecognized tax benefit (that will significantly increase or decrease within twelve months of the balance sheet date) for a tax position taken.

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The estimated upper bound of the reasonably possible change in the total amount of the unrecognized tax benefit (that will significantly increase or decrease within twelve months of the balance sheet date) for a tax position taken.

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The gross amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns as of the balance sheet date.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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