Stock-Based Compensation Plans (Summary Of Stock Option Activity) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Employee Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares, Outstanding at Beginning of Year	7,555	6,805	8,419
Shares, Granted	2,641	2,462	2,197
Shares, Exercised	(689)	(1,497)	(3,564)
Shares, Forfeited	(646)	(215)	(247)
Shares, Outstanding at End of Year	8,861	7,555	6,805
Shares, Exercisable at End of Year	3,003	2,024	1,767
Wtd. Avg. Ex. Price, Outstanding at Beginning of Year (usd per share)	$ 21	$ 17	$ 16
Wtd. Avg. Ex. Price, Granted (usd per share)	$ 20	$ 29	$ 21
Wtd. Avg. Ex. Price, Exercised (usd per share)	$ 15	$ 16	$ 17
Wtd. Avg. Ex. Price, Forfeited (usd per share)	$ 21	$ 19	$ 16
Wtd. Avg. Ex. Price, Outstanding at End of Year (usd per share)	$ 21	$ 21	$ 17
Wtd. Avg. Ex. Price, Exercisable at End of Year (usd per share)	$ 19	$ 17	$ 16
Wtd. Avg. Remaining Contract Life, Outstanding at End of Year	3 years 4 months 24 days	3 years 6 months	3 years 6 months
Wtd. Avg. Remaining Contract Life, Exercisable at End of Year	2 years 2 months 12 days	2 years 3 months 18 days	2 years 3 months 18 days
Aggregate Intrinsic Value, Exercised	$ 3,810	$ 20,659	$ 20,706
Aggregate Intrinsic Value, Outstanding at End of Year	11,730	66,295	85,374
Aggregate Intrinsic Value, Exercisable at End of Year	7,617	26,218	23,810
Non-Employee Director Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares, Outstanding at Beginning of Year	192	244	429
Shares, Granted	42	42	48
Shares, Exercised	0	(94)	(233)
Shares, Forfeited	0	0	0
Shares, Outstanding at End of Year	234	192	244
Shares, Exercisable at End of Year	234	192	244
Wtd. Avg. Ex. Price, Outstanding at Beginning of Year (usd per share)	$ 21	$ 18	$ 16
Wtd. Avg. Ex. Price, Granted (usd per share)	$ 22	$ 32	$ 21
Wtd. Avg. Ex. Price, Exercised (usd per share)	$ 0	$ 17	$ 16
Wtd. Avg. Ex. Price, Forfeited (usd per share)	$ 0	$ 0	$ 0
Wtd. Avg. Ex. Price, Outstanding at End of Year (usd per share)	$ 21	$ 21	$ 18
Wtd. Avg. Ex. Price, Exercisable at End of Year (usd per share)	$ 21	$ 21	$ 18
Wtd. Avg. Remaining Contract Life, Outstanding at End of Year	6 years 4 months 24 days	6 years 9 months 18 days	6 years 1 month 6 days
Wtd. Avg. Remaining Contract Life, Exercisable at End of Year	6 years 4 months 24 days	6 years 9 months 18 days	6 years 1 month 6 days
Aggregate Intrinsic Value, Exercised		1,362	1,932
Aggregate Intrinsic Value, Outstanding at End of Year	225	1,740	2,937
Aggregate Intrinsic Value, Exercisable at End of Year	$ 225	$ 1,740	$ 2,937