Incentive Stock Plans Schedule of Assumptions Used to Determine Fair Value, Options (Details) (Stock Options [Member], USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2011 Y	Dec. 31, 2010 Y	Dec. 31, 2009 Y
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Method Used	Black-Scholes option-pricing model
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	38.20%	37.80%	34.10%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	3.90%	4.70%	6.60%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	2.60%	3.20%	1.90%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	6.5	6.7	6.6
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 9.99	$ 7.07	$ 3.15
Share-based Compensation Arrangement by Share-based Payment Award, Options, Granted in Period, Total Grant Date Fair Value	$ 3.0	$ 2.8	$ 2.3

The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

For each plan, identification of the award pricing model or other valuation method used in calculating the weighted average fair values disclosed. The model is also used to calculate the compensation expense that is shown within the balance sheet, income statement, and cash flow. Examples of valuation techniques are lattice models (binomial model), closed-form models (Black-Scholes-Merton formula), and a Monte Carlo simulation technique. Fair value is the amount at which an asset or liability could be bought or incurred or sold or settled in a current transaction between willing parties, that is, other than in a forced or liquidation sale. May include disclosures about the assumptions underlying application of the method selected.

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