Stock-Based Compensation Plans (Schedule Of Weighted-Average Assumptions) (Details) (USD $)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Employee Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	2.70%	2.70%	2.60%
Expected volatility	41.60%	41.00%	39.20%
Risk-free interest rate	1.40%	2.00%	2.30%
Expected term of options (in years)	4.2	4.3	4.4
Weighted-average grant-date fair value	$ 8	$ 6	$ 4
Non-Employee Director Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	2.70%	2.70%	2.60%
Expected volatility	40.50%	40.80%	38.30%
Risk-free interest rate	3.20%	3.50%	2.90%
Expected term of options (in years)	6.5	8.1	8.7
Weighted-average grant-date fair value	$ 11	$ 8	$ 4

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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